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    Using a truss-inspired model with the uniform strength optimization theory to predict spongy bone geometry in proximal femur

    , Article American Journal of Applied Sciences ; Volume 6, Issue 3 , 2009 , Pages 449-455 ; 15469239 (ISSN) Pishdast, H ; Farahmand, F ; Rouhi, G. R ; Sharif University of Technology
    This paper presents a new naïve approach for simulating bone remodeling process. It is based on the uniform strength theory of optimization and employs a truss-like model for bone. The truss was subjected to external loads including 5 point loads simulating the hip joint contact forces and 3 muscular forces at the attachment sites of the muscles to the bone and the rest are reactions of ligaments. The strain in the links was calculated and the links with high strains were identified. The initial truss is modified by introducing new links wherever the strain exceeds a prescribed or critical value. The critical value was assumed to be equal to an average of the absolute value of strains in the... 

    Targeted nanomedicines for the treatment of bone disease and regeneration

    , Article Medicinal Research Reviews ; 2020 Ordikhani, F ; Zandi, N ; Mazaheri, M ; Luther, G. A ; Ghovvati, M ; Akbarzadeh, A ; Annabi, N ; Sharif University of Technology
    John Wiley and Sons Inc  2020
    Targeted delivery by either passive or active targeting of therapeutics to the bone is an attractive treatment for various bone related diseases such as osteoporosis, osteosarcoma, multiple myeloma, and metastatic bone tumors. Engineering novel drug delivery carriers can increase therapeutic efficacy and minimize the risk of side effects. Developmnet of nanocarrier delivery systems is an interesting field of ongoing studies with opportunities to provide more effective therapies. In addition, preclinical nanomedicine research can open new opportunities for preclinical bone-targeted drug delivery; nevertheless, further research is needed to progress these therapies towards clinical... 

    Comparison of the effects of different implant apical designs on the magnitude and distribution of stress and strain in bone: A finite element analysis study

    , Article Journal of Long-Term Effects of Medical Implants ; Vol. 24, issue. 2-3 , 2014 , p. 109-120 Kadkhodazadeh, M ; Lafzi, A ; Raoofi, S ; Khademi, M ; Amid, R ; Movahhedy, M. R ; Torabi, H ; Sharif University of Technology
    Objectives: The aim of this study was to investigate the effects of implant design on the apex area and on stress and stress patterns within surrounding bone. Methods: Three commercially available implants with the same diameter (3.5 mm), same length (10-11 mm), and same complement abutment were selected for modeling as follows: (1) flat apical design with light tapering degree, (2) dome-shaped apical design with light tapering, and (3) flat apical design with intense tapering in one-third of the apical area. According to human cone-beam computed tomography (CBCT), the bone was modeled using a cortical thickness of 2 mm and cancellous bone. Forces of 100 N and 300 N in the vertical and 15°... 

    The effect of microthread design on magnitude and distribution of stresses in bone: a three-dimensional finite element analysis

    , Article Dental Research Journal ; Volume 15, Issue 5 , 2018 , Pages 347-353 ; 17353327 (ISSN) Golmohammadi, S ; Eskandari, A ; Movahhedy, M. R ; Shirmohammadi, A ; Amid, R ; Sharif University of Technology
    Background: The researches regarding the influence of microthread design variables on the stress distribution in bone and a biomechanically optimal design for implant neck are limited. The aim of the present study is to compare the effect of different microthread designs on crestal bone stress. Materials and Methods: Six implant models were constructed for three-dimensional finite element analysis including two thread profile (coarse and fine) with three different lengths of microthreaded neck (1 mm, 2 mm, and 3 mm). A load of 200 N was applied in two angulations (0° and 30°) relative to the long axis of the implant and the resultant maximum von Mises equivalent (EQV), compressive, tensile,... 

    Effect of geometry on the fixation strength of anterior cruciate ligament reconstruction using BASHTI technique

    , Article Journal of Knee Surgery ; September , 2020 Moeinnia, H ; Nourani, A ; Borjali, A ; Mohseni, M ; Ghias, N ; Korani, H ; Chizari, M ; Sharif University of Technology
    Georg Thieme Verlag  2020
    The goal of this study is to investigate the effects of tendon and cannulated drill bit diameter on the strength of the bone and site hold tendon inside (BASHTI) fixation technique for an anterior cruciate ligament (ACL) reconstruction. Bovine digital tendons and Sawbones blocks were used to mimic the ACL reconstruction. Mechanical strength of the specimens was measured using a cyclic loading continued by a single cycle pullout load until failure to simulate the real postsurgical loading conditions. Finally, failure modes of specimens and ultimate failure load were recorded. The maximum possible tendon surface strain (i.e., tendon compression [TC]) for tendon diameters of 6, 7, 8, and 9 mm... 

    The wide-open three-legged parallel robot for long-bone fracture reduction

    , Article Journal of Mechanisms and Robotics ; Volume 9, Issue 1 , 2017 ; 19424302 (ISSN) Abedinnasab, M. H ; Farahmand, F ; Gallardo Alvarado, J ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2017
    Robotic reduction of long bones is associated with the need for considerable force and high precision. To balance the accuracy, payload, and workspace, we have designed a new six degrees-offreedom three-legged wide-open robotic system for long-bone fracture reduction. Thanks to the low number of legs and their nonsymmetrical configuration, the mechanism enjoys a unique architecture with a frontally open half-plane. This facilitates positioning the leg inside the mechanism and provides a large workspace for surgical maneuvers, as shown and compared to the well-known Gough-Stewart platform. The experimental tests on a phantom reveal that the mechanism is well capable of applying the desired... 

    Dynamic simulation of biomechanical behaviour of the pelvis in the lateral impact loads

    , Article Journal of Healthcare Engineering ; Volume 2018 , 2018 ; 20402295 (ISSN) Hatami, M ; Wang, D ; Qu, A ; Xiangsen, Z ; Wang, Q ; Baradaran Kazemian, B ; Sharif University of Technology
    The objective of this study was to develop and validate a novel 3D dynamic model of a pelvic side-impactor system. The biomechanical responses of a pelvic flexible model (having.mnf file suffix) under the lateral impact load for predicting the bone fracture mechanism are investigated as well. The 3D solid model of the side-impactor system was imported into MSC/ADAMS software for analyzing the dynamic model, and the pelvic flexible model was extracted from the CT images of a Chinese female volunteer. The flexible model of the pelvis system was developed considering a wide range of mechanical properties in the bone complex and soft tissue to achieve a realistic biomechanical response during a... 

    Fabrication of Bioactive Bone Cement

    , M.Sc. Thesis Sharif University of Technology Mansoori Kermani, Amir Reza (Author) ; Bahrevari, Mohammad Reza (Supervisor)
    PMMA bone cement lacks biodegradability and the ability to bond with surrounding bone tissue. Therefore, the development of a new generation of bioactive bone cements that are biodegradable and possess adequate mechanical properties as well as desirable setting time is receiving remarkable interest.In this study, we have developed novel mineral-based bioactive bone cements. Our mineral bioactive bone cements were composed of Calcium Sulfate Hemihydrate, Bioactive Glass, and Tricalcium Silicate. Firstly, a binary system composed of Calcium Sulfate Hemihydrate and Bioactive Glass was optimized based on mechanical and setting behavior. Secondly, Tricalcium Silicate was added to the powder phase... 

    Nanomedicine applications in orthopedic medicine: State of the art

    , Article International Journal of Nanomedicine ; Volume 10 , 2015 , Pages 6039-6054 ; 11769114 (ISSN) Mazaheri, M ; Eslahi, N ; Ordikhani, F ; Tamjid, E ; Simchi, A ; Sharif University of Technology
    Dove Medical Press Ltd  2015
    The technological and clinical need for orthopedic replacement materials has led to significant advances in the field of nanomedicine, which embraces the breadth of nanotechnology from pharmacological agents and surface modification through to regulation and toxicology. A variety of nanostructures with unique chemical, physical, and biological properties have been engineered to improve the functionality and reliability of implantable medical devices. However, mimicking living bone tissue is still a challenge. The scope of this review is to highlight the most recent accomplishments and trends in designing nanomaterials and their applications in orthopedics with an outline on future directions... 

    Nonlinear interstory drift contours for idealized forward directivity pulses using "modified fish-bone" models

    , Article Advances in Structural Engineering ; Volume 18, Issue 5 , May , 2015 , Pages 603-627 ; 13694332 (ISSN) Khalo, A. R ; Khosravi, H ; Jamnani, H. H ; Sharif University of Technology
    Multi-Science Publishing Co. Ltd  2015
    Four 5-, 10-, 20- and 30-story moment frames, representing low-, mid-, and two high-rise structures, were subjected to a great number of idealized directivity pulses. The amplitudes and periods of pulses vary from 0.02 g to 1.0 g and 0.5 to 12 sec, respectively. Over 1400 nonlinear dynamic analyses of low- to high-rise moment frames were performed which were feasible through using modified fish-bone model. The distribution of interstory drift along the height was studied and two applied contours were proposed: (i) the maximum interstory drift contour, and (ii) the critical story contour. These contours were demonstrated versus the ratio of natural period of the structure to the pulse period... 

    Preparation and Characterization of Polyurethane/Carbon Nanoparticles Nanocomposite for Biomedical Applications (Orthopedic)

    , Ph.D. Dissertation Sharif University of Technology Alishiri, Maryam (Author) ; Shojaei, Akbar (Supervisor) ; Abd Khodaei, Mohammad Jafar (Supervisor)
    Present study demonstrated carbon nanoparticles/acrylate-terminated polyurethane composites as promising materials for bone implants applications. Neat polymer and composites containing nanoparticles at different loadings up to 2 wt % were prepared by in situ polymerization method. Morphological analysis exhibited that nanoparticles caused considerable phase separation between soft and hard domains as well as increased crystallinity. Mechanical analysis showed a significant improvement in mechanical properties. Maximum improvement in tensile properties of APUA was observed at 1 wt% loading of ND-HEAMs, namely 175% improvement in modulus. In vitro biocompatibility evaluation via culturing... 

    Simulation of the Cellular Dynamics of Bone Remodeling and its Control Mechanisms

    , M.Sc. Thesis Sharif University of Technology Amiri, Behnam (Author) ; Zohoor, Hassan (Supervisor) ; Sohrabpour, Saeed (Co-Advisor)
    Bone is one of the most important biomechanical organs in animal bodies which comprises of a dynamic tissue that can change its internal structure through remodeling process. A comprehensive understanding of this process is of great significance in prevention and cure of many bone diseases. Due to the special conditions of hard bone tissue, empirical studies on the details of bone processes is very costly and time consuming. Thus, mathematical models and in silico simulations are key to unraveling how bone homeostasis imbalance can lead to pathological conditions. Therefore, in the recent years, there has been an increasing interest in modeling bone remodeling process in cellular level. In... 

    Preparation a Bio-Composite Scaffold Containing Hydroxyapatite/Silver Faunctionalized Graphene Oxide/Chitosan for Bone Tissue Engineering

    , M.Sc. Thesis Sharif University of Technology Askarinya, Amir Hossein (Author) ; Nemati, Ali (Supervisor) ; Malek Khachatourian, Adrineh (Supervisor)
    Bone scaffolds are used to regenerate bone tissue and accelerate bone healing, for this purpose, an attempt was made to prepare biocompatible, biodegradable, low toxicity and non-allergenic scaffolds to help increase osteogenesis and improve bone infections. A porous multi-component composite of chitosan, hydroxyapatite, graphene oxide functionalized with silver was made to make the desired scaffolds. At first, graphene oxide was functionalized by silver ions using silver nitrate. The structure of silver graphene oxide nanocomposite was confirmed by scanning electron microscope (SEM), Fourier infrared spectroscopy (FT-IR), and ultraviolet (UV-Visible) spectroscopy. In the next step, a... 

    Anatomy of a domino accident: Roots, triggers and lessons learnt

    , Article Process Safety and Environmental Protection ; Volume 90, Issue 5 , 2012 , Pages 424-429 ; 09575820 (ISSN) Abdolhamidzadeh, B ; Hassan, C. R. C ; Hamid, M. D ; Farrokhmehr, S ; Badri, N ; Rashtchian, D ; Sharif University of Technology
    On July 24th, 2010, several explosions and fires devastated a hydrocarbon processing plant in Kharg Island, Iran. Four workers were killed and many others were severely injured. The plant became out of service for 80 days. The way the accident happened and its sequence was representing as a domino accident. In this paper, events leading up to the disaster have been analyzed in details. Graphic presentation techniques such as Fish Bone Analysis and Event Sequence Diagram (ESD) have been utilized to enhance the understanding of the accident mechanism. Finally major lessons learnt from this domino accident have been addressed  

    A novel method for production of foamy core@compact shell Ti6Al4V bone-like composite

    , Article Journal of Alloys and Compounds ; Volume 656 , 2016 , Pages 416-422 ; 09258388 (ISSN) Ahmadi, S ; Sadrnezhad, S. K ; Sharif University of Technology
    Elsevier Ltd 
    This paper presents a novel method for fabrication of bone-like Ti6Al4V foamy core@compact shell composite for utilization as substitutive implant for cortical bone having porous core. Seven prototypes with core-diameters of 0, 6, 8, 10, 12, 14 and 16 mm surrounded by dense shells of respective thicknesses 8, 5, 4, 3, 2, 1 and 0 were produced by an innovative two-stage packing/compaction sintering method. Density, porosity, Young's modulus and compression strength of the prototypes depended on the core diameter. Mechanical strength and Young's modulus of 10@16 (10 mm core, 16 mm diameter prototypes) resembled that of the human ulna bone. Creation of foam at the center was achieved by... 

    Biomechanical aspects of the scapula-glenoid fixation in a reverse shoulder implant

    , Article World Congress on Engineering 2016, WCE 2016, 29 June 2016 through 1 July 2016 ; Volume 2224 , 2016 , Pages 1205-1210 ; 20780958 (ISSN); 9789881404800 (ISBN) Popham, F ; Muhandiram, J ; Abulkhair, N ; Chizari, M ; Sharif University of Technology
    Newswood Limited  2016
    The reverse shoulder implant is an implant for total replacement of the glenohumeral joint of patients suffering from osteoarthritis and with a damaged rotator cuff. The problem that arises with these conjoined ailments is that the displacement of the humeral head causes limited movement of the upper limb, with vertical mobility restricted to only allow for the arm to ascend to roughly the height of the shoulder. Attaching the ball to the scapula and the socket to the top of the humerus fixes the centre of rotation of the joint to increase the moment arm over the healthy shoulder's original position enabling patients' movement and dexterity to return. In this study the numerical evaluation... 

    A 3-legged parallel robot for long bone fracture alignment

    , Article ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE 2017, 6 August 2017 through 9 August 2017 ; Volume 3 , 2017 ; 9780791858158 (ISBN) Abedinnasab, M. H ; Farahmand, F ; Gallardo Alvarado, J ; Computers and Information in Engineering Division; Design Engineering Division ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2017
    The reduction of long bone fractures is traditionally an invasive procedure with drawbacks of intense force, soft tissue damage, and, both, rotational and longitudinal malalignment. To combat these drawbacks, we applied a novel, wide open, threelegged, 6-DOF parallel robot, to the current surgical procedure. This platform will balance the accuracy, payload, and workspace for the surgeon, resulting in more efficient, successful surgeries. The experimental tests on a phantom reveal that the mechanism is well capable of applying the desired reduction steps against the large muscular payloads with high accuracy. © 2017 ASME  

    Green composites in bone tissue engineering

    , Article Emergent Materials ; 2021 ; 25225731 (ISSN) Jouyandeh, M ; Vahabi, H ; Rabiee, N ; Rabiee, M ; Bagherzadeh, M ; Saeb, M. R ; Sharif University of Technology
    Springer Nature  2021
    Natural and biodegradable polymers are of particular interest as green sources with low-cost and environmentally friendly features, and have been widely used for polymer composite development. The term “Green Composites” refers to polymer/filler systems in which polymer, filler, or sometimes both components are green in view of sources from which they are yielded or their biodegradability. Natural fibers obtained from plants, animals, and/or geological processes are a big class of green sources widely applied in green composite development. There has also been continued research on recycling of green composite as well as developing hybrid systems for advanced applications. In view of their... 

    Evaluation of Mechanical and Structural Properties of Titanium Bone Scaffolds

    , M.Sc. Thesis Sharif University of Technology Naddaf Dezfuli, Sina (Author) ; Sadrnezhad, Khatiboleslam (Supervisor) ; Shokrgozaar, Mohammad Ali (Co-Supervisor)
    Interconnected–pore titanium scaffolds were fabricated by sintering of compressed mixture of TiH1.924 and urea or NaCl. Urea was removed by evaporation during sintering and NaCl was removed with water. TiH1.924 was used to enhance gas evolution for perpetuation of foam formation. Morphological studies of the spacer-removed scaffolds showed that the spacer shapes were replicated to the pores. Minimization of stress concentration at walls of the pores was, hence, helped by utilization of the spacers with spherical particles. The scaffolds having relative densities of 0.34 to 0.65 consisted pores of 200 to 600 μm diameter, compression strengths of 51 to 260 MPa, Young’s modulus of 6.3 to 22.66... 

    Synthesis of Hydroxyapatite Nanoparticles through Sol-Gel Method and Fabrication of Chitosan/Hydroxyapatite Scaffold for Bone Replacement Tissue

    , M.Sc. Thesis Sharif University of Technology Behboodi, Panteha (Author) ; Nemati, Ali (Supervisor) ; Faghihi Sani, Mohammad Ali (Co-Supervisor)
    Hydroxyapatite is the most substantial inorganic component of bone tissue which displays great biocompability and bioactivity. Nevertheless, its mechanical properties is not appropriate for a bone substitiues. Therefore, it is used to improve the mechanical properties of polymer matrix composite scaffolds. In the present work chitosan as a polymeric matrix was employed to fabricate hydroxyapatite- chitosan biocomposite scaffolds. Sol-Gel method was employed to synthesize hydroxyapatite nano particles. Porous scaffolds were fabricated via freeze-drying by introducing two different cross linkers, Glutaraldehyde and Sodium Tripolyphosphate. Mechanical (compressive strength), biocampability and...