Search results for " engineering"
showing 10 items of 38291 documents
Treatment of Knee Osteoarthritis with Bone Marrow-Derived Mononuclear Cell Injection: 12-Month Follow-up.
2018
Objectives To evaluate the main symptoms of knee osteoarthritis (OA) and tissue structure changes after a single dose bone marrow–derived mononuclear cell (BM MNC) intra articular injection. Case series study. Patients with knee OA Kellgren Lawrence (K-L) grade II and III received 1 injection of BM MNC. The clinical results were analyzed with the Knee injury and Osteoarthritis Outcome Score (KOOS) and Knee Society Score (KSS) before, 3, 6, and 12 months after injection. Radiological evaluation was performed with a calibrated x-ray and the magnetic resonance (MR) imaging before and 6 to 7 months postinjection. Results A total of 34 knees were treated with BM MNC injections. Mean (±SD) age of…
Angiogenesis control in spine regeneration
2012
Abstract: The intervertebral disc (IVD) has a complex vascularisation pattern. While the nucleus pulposus is avascular, the annulus fibrosus as well as the endplates are vascularised. IVD degeneration is often accompanied, on the one hand, by blood vessel ingrowth into the nucleus pulposus and, on the other hand, by diminished vascularisation of the endplates. Tissue engineering of IVD, therefore, has to address the differences in the vascularisation of IVD compartments. This chapter summarises current knowledge about the mechanisms of angiogenesis and its physiological and pathological role in IVD biology. Different strategies to control angiogenesis are discussed in the chapter with examp…
Silicate modulates the cross-talk between osteoblasts (SaOS-2) and osteoclasts (RAW 264.7 cells): inhibition of osteoclast growth and differentiation
2012
It has been shown that inorganic monomeric and polymeric silica/silicate, in the presence of the biomineralization cocktail, increases the expression of osteoprotegerin (OPG) in osteogenic SaOS-2 sarcoma cells in vitro. In contrast, silicate does not affect the steady-state gene expression level of the osteoclastogenic ligand receptor activator of NF-κB ligand (RANKL). In turn it can be expected that the concentration ratio of the mediators OPG/RANKL increases in the presence of silicate. In addition, silicate enhances the growth potential of SaOS-2 cells in vitro, while it causes no effect on RAW 264.7 cells within a concentration range of 10-100 µM. Applying a co-cultivation assay system,…
Hydration process and rheological properties of cement pastes modified by orthophosphate addition
2005
Abstract The use of cement by nuclear industry for confining low radioactive waste knows a constant increase. The interest bore to this material is due to its mechanical and chemical properties. However, these properties may be modified by the nature and the amount of wastes introduced with the mixing solution especially with large amount of phosphate. Precipitation of hydroxylapatite in the cement paste at the very beginning after mixing was emphasized from a particular concentration of orthophosphate. It was also found that this phenomenon leads to an early rigidification of the cement paste. From a kinetics point of view, the evolution of hydration was both delayed and slowed down accord…
Imaging of Temporomandibular Joint: Approach by Direct Volume Rendering
2014
Background: The purpose of this study was to conduct a morphological analysis of the temporomandibular joint, a highly specialized synovial joint that permits movement and function of the mandible. Materials and Methods: We have studied the temporom-andibular joint anatomy, directly on the living, from 3D images obtained by medical imaging Computed Tomography and Nuclear Magnetic Resonance acquisition, and subsequent re-engineering techniques 3D Surface Rendering and Volume Rendering. Data were analysed with the goal of being able to isolate, identify and distinguish the anatomical structures of the joint, and get the largest possible number of information utilizing software for post-proces…
Comparisons of processing and strength properties of two adhesive systems for composite joints
2007
Abstract In the present study rheological, static and impact tests are carried out on two adhesive resins usually employed in marine applications; then single lap joint tests are conducted on composites joints evidencing the effect of the curing time of both resins on the mechanical properties of the joint. The applicability and workability conditions of the adhesive resins are determined evaluating the curing evolution by a preliminary rheological analysis; then the relation of curing properties with the mechanical performances of the resins themselves and with ones of the composite joints is estimated. Static flexural and Izod impact tests are performed on the resins at increasing time af…
In vitro comparison of the efficacy of two fractured implant-prosthesis screw extraction methods: Conventional versus mechanical.
2019
Abstract Statement of problem Implant-supported prostheses may be subject to esthetic, biological, or mechanical complications. Protocols for dealing with these mechanical problems are sparse. Purpose The purpose of this in vitro study was to compare the efficacy of a mechanical system for extracting fractured implant-prosthesis screws with the conventional method. Material and methods A total of 60 screws were divided into 2 groups according to their morphology (flat screws with a smooth shaft and threaded apical area and screws with a completely threaded body) and subjected to fatiguing and static load testing until fracture. The specimens were assigned to 3 operators with varying levels …
Bioengineered in vitro 3D model of myotonic dystrophy type 1 human skeletal muscle
2021
Abstract Myotonic dystrophy type 1 (DM1) is the most common hereditary myopathy in the adult population. The disease is characterized by progressive skeletal muscle degeneration that produces severe disability. At present, there is still no effective treatment for DM1 patients, but the breakthroughs in understanding the molecular pathogenic mechanisms in DM1 have allowed the testing of new therapeutic strategies. Animal models and in vitro two-dimensional cell cultures have been essential for these advances. However, serious concerns exist regarding how faithfully these models reproduce the biological complexity of the disease. Biofabrication tools can be applied to engineer human three-dim…
Analysis and optimization of hybrid double lap aluminum-GFRP joints
2014
In this paper a systematic investigation of the mechanical performance of hybrid double-lap Al-GFRP bonded-bolted joints, has been carried out by using experimental analyses and numerical simulations. In order to detect the optimal geometric configuration, as well as to highlight the contribution of adhesive and bolts, the results relative to hybrid joints have been compared with those of simply adhesively bonded and simply bolted joints. The experimental and numerical results have shown that by using the minimum overlap length provided from theory, the bolt leads to a significant decreasing of both the maximum shear and the maximum peel stresses in the adhesive layer and, consequently, the…
Redesign of a Reverse Shoulder Prosthesis: Kinematic and Mechanical Study
2014
In this work a commercial reverse shoulder prosthesis has been redesigned to improve performances in terms of range of movements of the implant and stability to dislocation. A kinematic and mechanic study has been performed using a realistic solid model of the prothesised shoulder: in particular, all the components of the prosthesis have been acquired via a 3D laser scanner and inserted in a virtual humerus-glenoid system by reproducing the common surgical procedure. The final model has been used to measure the maximum angles of abduction and rotation of the arm and the shear forces that cause dislocation. Modifications proposed to the commercial prosthesis are: a different orientation of t…