Search results for " radio"
showing 10 items of 2362 documents
Uusien 5G-teknologioiden energiatehokkuus
2016
Mobiiliverkkojen datamäärän kasvaessa räjähdysmäisesti tarvitaan uutta 5G-teknologiaa lisäämään langattomien verkkojen kapasiteettia. 5G-verkkoja kehitettäessä yksi tärkeä tutkimuskysymys on, kuinka saada niistä energiatehokkaita. Tässä tutkielmassa käydään läpi tieteellistä keskustelua aiheesta. Tieteellisestä keskustelusta keskeisimmiksi teknologioiksi 5G-verkkoihin nousevat muun muassa laitteistotekniikan kehittyminen, millimetriaallot, kognitiivinen radioverkko, massiivinen MIMO ja heterogeeninen verkko. Tarvitaan kuitenkin lisää tutkimusta ja kehitystyötä, jotta uusista 5G-verkoista saadaan riittävän energiatehokkaita. The amount of mobile data will grow radically and that's why we nee…
RADIOPROTECTION IN 2018: AN UPDATE
2018
Fluoroscopically-guided interventional procedures are performed in large numbers in Europe and in the United States. Radiation doses received by interventional radiologists can vary for the same type of procedure and for similar patient doses. Occupational radiation protection is a necessity whenever radiation is used in the practice of medicine. The International Commission on Radiological Protection is engaging against occupational radiation damages, publishing regular recommendations on dose limits. These limits are expressed as effective doses for the whole body and also as equivalent doses for particular regions or tissues of practitioners’ bodies. Shielding and personal protective clo…
An Exact Solution for the Level-Crossing Rate and the Average Duration of Fades of the Envelope of Sum-of-Cisoids Processes
2012
Authors version of an article published in the journal: Procedia Technology. Also available from the publisher at: http://dx.doi.org/10.1016/j.protcy.2012.03.004 Sum-of-cisoids (SOC) processes provide a physically and numerically appealing framework for the modelling and simulation of a wide class of mobile radio channels. This paper is concerned with the problem of finding a general solution for the level-crossing rate (LCR) and the average duration of fades (ADF) of the envelope of SOC processes. Exact expressions are derived for the LCR and the ADF by taking into account that the inphase component, the quadrature component, and the time derivatives of the inphase and quadrature component…
The migration of femoral components after total hip replacement surgery: accuracy and precision of software-aided measurements.
2003
To assess the accuracy and precision of a software-aided system to measure migration of femoral components after total hip replacement (THR) on digitised radiographs.Subsidence and varus-valgus tilt of THR stems within the femur were measured on digitised anteroposterior pelvic radiographs. The measuring software (UMA, GEMED, Germany) relies on bony landmarks and comparability parameters of two consecutive radiographs. Its accuracy and precision were calculated by comparing it with the gold standard in migration measurements, radiostereometric analysis (RSA). Radiographs and corresponding RSA measurements were performed in 60 patients (38-69 years) following cementless THR surgery.The UMA s…
Hoffa’s fat pad thickness: a measurement method with sagittal MRI sequences
2021
Abstract Background Hoffa’s fat pad is a structure located within the fibrous joint capsule of the knee joint, but outside the synovial cavity. It plays an important biomechanical and metabolic role in knee joint, reducing the impact of forces generated by loading and producing cytokines. Changes in its size can induce modifications in the knee homeostasis. However, a great variability exists regarding its measurements. This work aims to evaluate the reliability of a measurement method of Hoffa’s fat pad dimensions through MRI. Methods 3T sagittal IW 2D TSE fat-suppressed MRI sequences, taken from the OAI (Osteoarthritis initiative) database, of 191 male and female patients, aged between 40…
Dairy calcium intake and lifestyle risk factors for bone loss in hiv-infected and uninfected mediterranean subjects
2012
Abstract Background Despite the reported high prevalence of osteoporosis in the human immunodeficiency virus (HIV)-population, there have been no previous studies examining dairy calcium intake and bone mineral density (BMD) in HIV-subjects. We assessed the prevalence of low BMD in HIV-infected and uninfected subjects and analyzed the effects of calcium intake, lifestyle and HIV-related risk factors on BMD. Methods One hundred and twelve HIV-infected subjects were consecutively enrolled. Seventy- six HIV-uninfected subjects matched for age and sex were enrolled as the control group. The HIV-subjects were interviewed about lifestyle habits and completed a weekly food-frequency questionnaire …
Reduction rate by decompression as a treatment of odontogenic cysts
2017
Background: Odontogenic cysts are defined as those cysts that arise from odontogenic epithelium and occur in the tooth-bearing regions of the jaws. Cystectomy, marsupialization or decompression of odontogenic cyst are treatment approach to this pathology. The aim of this study was to evaluate the effectiveness of the decompression as the primary treatment of the cystic lesions of the jaws and them reduction rates involving different factors. Material and Methods: 23 patients with odontogenic cysts of the jaws, previously diagnosed by anatomical histopathology (follicular cysts (7) and radicular cysts (16)) underwent decompression as an initial treatment. Clinical examination and pre and pos…
The campomelic syndrome: review, report of 17 cases, and follow-up on the currently 17-year-old boy first reported by Maroteaux et al in 1971.
1983
We report 17 cases of the campomelic syndrome (CS) and a follow-up of one of the original patients of Maroteaux et al who is now 17 years old. Our review is based on 97 patients, including our own. An infant with the CS presents at birth with spectacularly short and bowed femora and tibiae. The initial chest radiograph confirms the diagnosis by demonstrating extremely small bladeless scapulae and hypoplastic pedicles of many thoracic vertebrae. Ossification of the sternal segments, pubis, talus, and knee epiphyses is also retarded. Usually the hips are dislocated and talipes equinovarus deformities are present. There is a small chondrocranium and a disproportionately large neurocranium. The…
Maxillary bone lesions in McCune-Albright syndrome:a case report
2011
Abstract Objectives In this study, we report on the clinical maxillary manifestations of a patient affected by McCune-Albright syndrome and the implications for orthodontic therapy. Materials and methods A male, 8-year-old patient was examined at the Department of Orthodontics of the University of L’Aquila for a problem of anterior open-bite. In the clinical examination, a small swelling of the left hemi-maxilla was seen in the area corresponding to the root apex of 16 and under the tooth buds of 14 and 15. In a panoramic radiograph, a radio-opaque area was detected in this zone. From the computer tomography examination, a bone lesion was identified. Results Identification of this bone lesi…
MRI findings and physical performance as predictors of flight-induced musculoskeletal pain incidence among fighter pilots
2017
Summary Study aim: The aim of this study was to evaluate the possible association of pre-career magnetic resonance imaging (MRI) findings and physical performance level with possible musculoskeletal disorders during jet flight training. Material and methods: The study group consisted of 73 fighter pilots who had undergone pre-career cervical and lumbar spine MRI. Physical performance of a subgroup of the pilots (n = 67) was measured initially at the same time and followed up to the fast jet training phase (ranging from 3.8 to 7.0 years). Musculoskeletal pain history during pilot training was taken from the medical charts. MRI findings and physical performance were associated with perceived…