144 research outputs found

    Operational Overview for UAS Integration in the NAS Project Flight Test Series 3

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    The National Aeronautics and Space Administration Unmanned Aircraft Systems Integration in the National Airspace System Project has conducted a series of flight tests intended to support the reduction of barriers that prevent unmanned aircraft from flying without the required waivers from the Federal Aviation Administration. The 2015 Flight Test Series 3, supported two separate test configurations. The first configuration investigated the timing of Detect and Avoid alerting thresholds using a radar equipped unmanned vehicle and multiple live intruders flown at varying encounter geometries. The second configuration included a surrogate unmanned vehicle (flown from a ground control station, with a safety pilot on board) flying a mission in a virtual air traffic control airspace sector using research pilot displays and Detect and Avoid advisories to maintain separation from live and virtual aircraft. The test was conducted over an eight-week span within the R-2508 Special Use Airspace. Over 200 encounters were flown for the first configuration, and although the second configuration was cancelled after three data collection flights, Flight Test 3 proved to be invaluable for the purposes of planning, managing, and execution of this type of integrated flight test

    Functional endoscopic sinus surgery (FESS) with navigation system in childhood – our experience. Presentation of clinical cases

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    Introduction: Functional endoscopic sinus surgery (FESS) is the gold minimally invasive standard in diagnosing and surgically treating many diseases of the nose and paranasal cavities. An advantage of FESS is the possibility of application in all age groups.Materials and methods: We observed pediatric patients attended the Otorhinolaryngology Clinic in the University Hospital “Dr. Georgi Stranski” – Pleven in 2021. FESS surgery was performed in the “Integrated interdisciplinary operating unit with navigation and telesurgery systems” at the Center of competence on personalised medicine, 3D and telemedicine, robotic and minimally invasive surgery „Leonardo da Vinci” in Medical University – Pleven.Clinical cases: Case 1: A 7-year-old male patient with orbital complication of rhinosinusitis, with left orbital preseptal cellulitis, without ophthalmoplegia or loss of vision, + ptosis of the eyelid and data on pansinuitis from CT images. Performed FESS found lysis of lamina papyracea with involvement of anterior and posterior ethmoidal cells. Postoperative treatment was done with Ceftriaxone 1g/12h i.v. for 7 days, nasal glucocorticoids and antihistamines.Case 2: A 17-year-old female patient with suggested primary ciliary dyskinesia with a recurrent rhinosinusitis, persistent nasal obstruction, and thick viscous secretions that did not respond to conservative treatment. Sweat test for cystic fibrosis (-). FESS reshaping of the natural openings of the maxillary sinuses and anterior ethmoidectomy were performed bilaterally.Conclusion: FESS is a minimally invasive method, which is suitable for application in pediatric patients. When applied by trained professionals, FESS with an integrated navigation system is optimal for the diagnosis and surgical treatment of chronic and acute rhinosinusitis in children

    Microorganisms colonizing tooth structures and antibacterial effect of temporary filling materials

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    The oral cavity contains a variety of microorganisms. Some of them are pathogens. Various groups of microorganisms play roles in causing different diseases affecting the hard dental tissues, the pulp, and the periodontium. The microflora found in dentin, the pulp chamber, and the root canals closely resembles that present in the oral cavity. While most of these microorganisms are part of the normal oral microbiota, they can acquire pathogenic characteristics under certain conditions.The aim of this research is to study different types of microorganisms that inhabit tooth structures and assess the antibacterial properties of temporary filling materials.A series of related articles, publications, and results of different studies have been analyzed and summarized in order to provide an overview of the main pathogens affecting the hard dental tissues, the pulp, and the periodontium, as well as the antibacterial properties of temporary filling materials.The literature review of the articles shows that many species affect the dental tissues, and different medications and strategies for their elimination are needed.Furthermore, the review highlights that temporary filling materials have antimicrobial properties against certain microorganisms and have to be combined with different intracanal dressings

    Secondary peak on asymmetric magnetization loop of type-II superconductors

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    Asymmetric magnetization loops with a second peak effect were parameterized by the extended critical state model. The magnetic field distribution in a sample is considered. Expression is suggested for a peak of the critical current density and corresponding depression on field dependence of the depth of surface layer with equilibrium magnetization. These functions determine the width and the asymmetry of a magnetization loop. Asymmetry of the secondary peak height on magnetization branches for increasing and decreasing field is reproduced on the computed magnetization curves.Comment: 6 pages, 2 figures, Equation 6 is modified to be f=0 at B=

    Our experience in the surgical treatment of Obstructive Sleep Apnea

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    Background: Obstructive Sleep Apnea (OSA) is a sleep-related breathing disorder, leading to decreased quality of life, increased risk of cardiovascular morbidity and mortality, increased frequency of automobile accidents. Continuous positive airway pressure (CPAP) remains the first line of treatment for OSA. Many patients are unwilling or incapable to tolerate the treatment and therefore turn to surgical options to alleviate symptoms and sequela of the disease.Аim: To present our experience in the surgical treatment of OSA.Materials and Methods: 50 patients (48 male / 2 female) underwent surgical treatment for OSA in our clinic for a period of 10 years. Subjective complaints were evaluated by interview of the patient and partner pre- and postoperatively, with key factors studied being snoring level (visual analogue 1–10) and Epworth Sleepiness Scale (ESS). Objective data were Body Mass Index (BMI), nasal endoscopy, pre and postoperative polysomnographic data, rhinomanometry, Mallampati score, diagnostic imaging of the nose and sinuses.Results: The mean BMI of the patients was 29.8± 3.4. 21 patients had nasal obstruction for which they underwent surgical treatment. 5 patients had micro or retrognathia. 37 Pateints had a Mallampati score of 3 and 13 of 4. All 50 patients underwent Uvulopalatopharyngoplasty (UPPP) and 6 patients also had Radiofrequency tongue base reduction. There were no serious complications. Subjective improvement in the severity of the symptoms was obtained in 88% (44) of patients. Objective success was obtained in 56% (28) of the patients.Conclusions: Surgical treatment of OSA leads to a significant subjective improvement in the severity of symptoms and acceptable objective results. For maximal results a multidisciplinary approach is required for the complex treatment of OSA

    Estimation of errors in text and data processing

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    The company Adiss Lab Lts. obtained 1 000 000 medical reports that are either in free form text, or in XML format. One of the main goals of their development is to integrate an algorithm for information extraction (IE) in their platform. The verification of the algorithm’s output for a report is done by a medical doctor (MD) for a certain fee. Validating the correctness of all data would be overwhelming and very expensive. Hence, the problem, as presented by the company, is to provide a method (algorithm) which determines the minimum amount of reports that will validate the correctness of the IE algorithm and a procedure for selecting these reports. In order to solve the problem we have considered an algorithm-centric approach uses active learning and semi-supervised learning

    The application of ultrasound examination in the treatment of Acute Sinusitis. Comparing X-ray to ultrasound of paranasal sinuses

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    Background: Acute rhinosinusitis (ARS) is one of the most common diseases encountered in the out-patient setting. X-ray of the paranasal sinuses is the gold standard in the diagnosis of ARS with its accessibility and accuracy. Ultrasound examination of the paranasal sinuses is a noninvasive diagnostic method which is an acceptable alternative in the follow-up of the treatment.Aim: To present the application of portable sinuson in the out-patient setting on patients with ARS and its effectiveness.Materials and Methods: 22 patients (12m/10f) underwent X-ray of the paranasal sinuses, which resulted in ARS. The results of the X-rays were compared with the ultrasound examination of the paranasal sinuses with a portable sinuson (SINUSULTRA ULTRAMAX). The examination was repeated on the 1-st and 2-nd week and 2 months after the treatment for ARS.Results: From the 22 patients – 10 were with unilateral maxillary sinusitis, 7 with bilateral sinusitis and 5 with pansinusitis. 5 (22%) false positives were registered from the ultrasound examination on the initial check-up, 3 (13%) false negatives were registered on the follow-ups on the 1-st and the 2-nd week, 2 (9%) false negatives were registered 2 months after the treatment for ARS.Conclusion: Ultrasound examination of the paranasal sinuses is a noninvasive, painless, fast and with an adequate degree of accuracy. It is a good alternative for children and pregnant women. Ultrasound examination can be applied in the follow-up of ARS

    Quantum phase transitions and thermodynamic properties in highly anisotropic magnets

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    The systems exhibiting quantum phase transitions (QPT) are investigated within the Ising model in the transverse field and Heisenberg model with easy-plane single-site anisotropy. Near QPT a correspondence between parameters of these models and of quantum phi^4 model is established. A scaling analysis is performed for the ground-state properties. The influence of the external longitudinal magnetic field on the ground-state properties is investigated, and the corresponding magnetic susceptibility is calculated. Finite-temperature properties are considered with the use of the scaling analysis for the effective classical model proposed by Sachdev. Analytical results for the ordering temperature and temperature dependences of the magnetization and energy gap are obtained in the case of a small ground-state moment. The forms of dependences of observable quantities on the bare splitting (or magnetic field) and renormalized splitting turn out to be different. A comparison with numerical calculations and experimental data on systems demonstrating magnetic and structural transitions (e.g., into singlet state) is performed.Comment: 46 pages, RevTeX, 6 figure

    Rare earth elements materials production from apatite ores

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    The paper deals with the study of processing apatite ores with nitric acid and extraction of the rare earth elements. The rare earth elements can be successfully separated and recovered by extraction from the nitrate- phosphate solution, being an tributyl phosphate as extraction agent. The developed scheme of the processing apatite concentrate provides obtaining rare earth concentrates with high qualitative characteristics

    Extraction of rare earth elements from hydrate-phosphate precipitates of apatite processing

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    The features of extraction of rare earth elements (REE) were considered from hydrate-phosphate precipitates of REE of apatite processing by nitric acid technology. The preliminary purification of nitrate solution of REE from impurities of titanium, aluminum, iron, uranium and thorium was suggested to obtain stable solutions not forming precipitates. Washing the extract was recommended with the evaporated reextract that allows to obtain directly on the cascade of REE extraction the concentrated solutions suitable for the separation into groups by the extraction method. Technical decisions were suggested for the separation of REE in groups without the use of salting-out agent
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