Search results for "atomic"
showing 10 items of 27529 documents
Posterior Tibial Tendon Dislocation: A Case Report
2022
Abstract Isolated posterior tibial tendon dislocation is a rare condition. Diagnosis can be challenging, especially in the acute clinical setting. Predisposing factors include shallow posterior tibial tendon groove and tear of the flexor retinaculum. We report the case of traumatic subluxation of the posterior tibial tendon, illustrating imaging findings and surgical technique. Posterior tibial tendon dislocation was detected using dynamic ultrasound, while magnetic resonance was essential for a comprehensive evaluation that included underlying predisposing anatomic abnormalities and associated pathologic conditions. Conservative treatment is often unsuccessful thus surgical approach was ne…
Juxtacortical mandibular chondrosarcoma during pregnancy : a case report
2017
Chondrosarcoma is one of the most common malignant bone tumors in adults. It use to affect upper arm, pelvis and thigh bone. A wide surgical extirpation represent the gold standard to treat this disorder. In fact, radiotherapy and chemotherapy are no useful. Interestingly, chondrosarcoma is rare in head and neck (HNCS) and extremely uncommon during pregnancy. Thus, there is a lack of evidence about the proper treatment in these cases. A wide surgical extirpation is also considered the most effective procedure in HNCS. There are no consistent evidences about the he role of radiation and chemotherapy. In view of that, the present study describes a case of juxtacortical mandibular chondrosarco…
Upper Limb Interventions.
2019
Ultrasound has been reported to be a quick, cheap, and effective imaging modality to guide the interventional procedures in the musculoskeletal system. The use of ultrasound results in increased accuracy of needle placement associated with a reduction of complications. In the upper limb, ultrasound-guided procedures are applied to joints and soft tissues around the shoulder, elbow, wrist, and hand. This article reviews the clinical and technical aspects of the most common procedures performed in this anatomic area.
The effect of cement fixation on initial micromotion of the femoral component in condylar knee replacement
1992
Four fresh, cadaveric specimens were fitted with total knee replacements and mounted on a knee joint loading and measuring rig. Femoral component micromotion in the sagittal plane was measured with a transducer during flexion and extension of the specimen. Various condylar designs were used without and with cement. Movement followed a characteristic curve pattern and was less with cement fixation particularly for bone of low trabecular strength as determined by bone sample tests for stiffness. Cement fixation appears to be superior to cementless fixation.
The impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease
2021
This study investigated the impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease (NAFLD). A total of 63 eligible women randomly participated in the Nordic walking training (AEx, n = 33), or maintained their daily lifestyle (Con, n = 30) during intervention. Bone mineral content (BMC) and density (BMD) of whole body (WB), total femur (TF), femoral neck (FN), and lumbar spine (L2-4) were assessed by dual-energy X-ray absorptiometry. Serum osteocalcin, pentosidine, receptor activator of nuclear factor kappa-B ligand (RANKL) levels were analyzed by ELISA assay. After an 8.6-month intervention, the AEx group maintained their BM…
Nanoscale mechanical characterization of polymers by atomic force microscopy (AFM) nanoindentations: Viscoelastic characterization on a model material
2009
The Atomic Force Microscope (AFM), apart form its conventional use as a microscope, is also used for the characterization of the local mechanical properties of polymers. In fact, the elastic characterization of purely elastic materials using this instrument can be considered as a well assessed technique while the challenge remains the characterization of the viscoelastic mechanical properties. In particular, one finds the mechanical behavior changing when performing indentations at different loading rates, i.e., on different time scales. Moreover, this apparent viscoelastic behavior can also be due to complex contact mechanics phenomena, with the onset of plasticity and long-term viscoelast…
Bright Visible Luminescence in Silica Nanoparticles
2011
International audience; We demonstrate that a porous film of silica nanoparticles emits a bright visible luminescence associated with defects stabilized by oxygen chemisorption at oxygen deficient center sites. Time-resolved spectra excited by a tunable laser allow us to distinguish the luminescence at 1.99 eV, characteristic of the nonbridging oxygen hole center (NBOHC) (Si-O)3 Si-O*, and a fast and a slow emission: the first (lifetime τ ≈ 25 ns) is peaked at 2.27 eV with an excitation spectrum centered at 5.5 eV; the second (τ ≈ 7.5 μs) is peaked at 2.41 eV and is excited around 3.2 and 5.2 eV. Reaction in an air atmosphere leads to the disappearance of the NBOHC luminescence and of the …
Luminescence properties of neodymium-doped yttrium aluminium garnet obtained by the co-precipitation method combined with the mechanical process
2005
Nanopowders of yttrium aluminium garnet Y3Al5O12 (YAG) doped with neodymium ions were obtained by the co-precipitation method from the reaction of aluminium and yttrium nitrate and neodymium oxide with ammonia. After washing and drying the hydroxide precursors were calcined at 500, 700, 800 and 900 °C for 1 hour and at 1000 °C for 3 hours. This product was treated by ball milling in a zirconia vial for 0.5, 1.5 and 10 h in order to achieve smaller nanoparticles. The structure, microstructure, morphology and optical properties were investigated by means of diffractometric, microscopic and spectroscopic techniques. The course of the amorphous-to-crystalline transformation was complete after c…
Second Harmonic Emission From Dielectric Nanoresonators in the Absorption Regime
2023
We study second harmonic generation in dielectric nanocylinders as a function of the wavelength of the incident field and geometrical dimensions. Uncommonly, we consider a spectral range in which the emitted nonlinear signal is partially absorbed by the dielectric. Surprisingly, we reveal that the second harmonic efficiency does not decrease as the imaginary part of the complex dielectric refractive index increases. Indeed, the presence of higher order multipoles supported by the resonators at the fundamental wavelength can significantly boost the generated second harmonic signal even in the dielectric absorption spectral region achieving nonlinear efficiency of the same order of magnitude …
A Navigation and Augmented Reality System for Visually Impaired People
2021
In recent years, we have assisted with an impressive advance in augmented reality systems and computer vision algorithms, based on image processing and artificial intelligence. Thanks to these technologies, mainstream smartphones are able to estimate their own motion in 3D space with high accuracy. In this paper, we exploit such technologies to support the autonomous mobility of people with visual disabilities, identifying pre-defined virtual paths and providing context information, reducing the distance between the digital and real worlds. In particular, we present ARIANNA+, an extension of ARIANNA, a system explicitly designed for visually impaired people for indoor and outdoor localizati…