Loading...
Search for:
medical-applications
0.007 seconds
Total 134 records
Noise reduction in OCT skin images
, Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 12 February 2017 through 14 February 2017 ; Volume 10137 , 2017 ; 16057422 (ISSN) ; 9781510607194 (ISBN) ; Fatemizadeh, E ; Adabi, S ; Mehregan, D ; Daveluy, S ; Nasiriavanaki, M ; Gimi, B ; Krol, A ; Sharif University of Technology
Abstract
OCT skin images suffer from artifacts. Speckle is the main artifact while the other one is called background noise. In this study, we propose an algorithm that significantly reduces the background noise before applying a speckle reduction method. The results show that the diagnostically relevant features in the images become clearer after applying the proposed method. We used sub-pixel weighted median filtering for speckle reduction. The results from background noise removal in combination with the proposed speckle reduction algorithm show a significant improvement in the clarity of diagnostically relevant features in in-vivo human skin images. © 2017 SPIE
Time-delay compensation and disturbance rejection in the control of robots with visco-elastic joints using loop-shaping approach
, Article 2007 IEEE International Workshop on Robotic and Sensor Environments, ROSE 2007, Ottawa, ON, 12 October 2007 through 13 October 2007 ; October , 2007 , Pages 46-50 ; 1424415276 (ISBN); 9781424415274 (ISBN) ; Taher, M ; Dehestani Ardekani, R ; Jahed, M ; Sharif University of Technology
2007
Abstract
In many medical applications, it is necessary to precisely control a robot to achieve exact positioning. In such cases, some components of robot which had been considered rigid should be modeled with visco-elastic elements to present more exact model of robot, and hence controllers designed under the assumption of rigidity may not accurately control them, especially when time-delay and disturbances have been appeared in the closed-loop system. In this study, we present a new control approach to force such robots to have rigid and exact motions, while they have visco-elastic components. Time-delay in the feedback path defects transient state response, while disturbances change the steady...
Content based mammogram image retrieval based on the multiclass visual problem
, Article 2010 17th Iranian Conference of Biomedical Engineering, ICBME 2010 - Proceedings, 3 November 2010 through 4 November 2010, Isfahan ; 2010 ; 9781424474844 (ISBN) ; Fatemizadeh, E ; Sharif University of Technology
2010
Abstract
Since expertise elicited from past resolved cases plays an important role in medical application and images acquired from various cases have a great contribution to diagnosis of the abnormalities, Content based medical image retrieval has become an active research area for many scientists, In this article we proposed a new framework to retrieve visually similar images from a large database, in which visual relevance is regarded as much as the semantic category similarity, we used optimized wavelet transform as the multi-resolution analysis of the images and extracted various statistical SGLDM features from different resolutions then after reducing feature space we used error correcting codes...
Polysaccharide-based nanocomposites for biomedical applications: a critical review
, Article Nanoscale Horizons ; Volume 7, Issue 10 , 2022 , Pages 1136-1160 ; 20556756 (ISSN) ; Shokrani, A ; Sajadi, S. M ; Khodadadi Yazdi, M ; Seidi, F ; Jouyandeh, M ; Zarrintaj, P ; Kar, S ; Kim, S. J ; Kuang, T ; Rabiee, N ; Hejna, A ; Saeb, M. R ; Ramakrishna, S ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Polysaccharides (PSA) have taken specific position among biomaterials for advanced applications in medicine. Nevertheless, poor mechanical properties are known as the main drawback of PSA, which highlights the need for PSA modification. Nanocomposites PSA (NPSA) are a class of biomaterials widely used as biomedical platforms, but despite their importance and worldwide use, they have not been reviewed. Herein, we critically reviewed the application of NPSA by categorizing them into generic and advanced application realms. First, the application of NPSA as drug and gene delivery systems, along with their role in the field as an antibacterial platform and hemostasis agent is discussed. Then,...
Efficient implementation of real-time ECG derived respiration system using cubic spline interpolation
, Article Proceedings - IEEE International Symposium on Circuits and Systems ; 2013 , Pages 1083-1086 ; 02714310 (ISSN) ; 9781467357609 (ISBN) ; Ehsani, S. P ; Shabany, M ; Sharif University of Technology
2013
Abstract
Monitoring the respiratory signal is crucial in many medical applications. Traditional methods for the respiration measurement are normally based on measuring the volume of air inhaled and exhaled by lungs (like spirometer) or oxygen saturation in blood. However, these methods have numerous challenges including their high cost and not being accessible in some cases. In this paper, an algorithm for deriving the respiratory signal from ECG signal is proposed, which is based on other proposed algotithms. This algorithm uses the cubic spline interpolation (CSI) of R-waves in ECG to derive the respiratory signal. The CSI algorithm is made efficient with respect to ECG features in order to reduce...
Nonlinear bilateral adaptive impedance control with applications in telesurgery and telerehabilitation
, Article Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME ; Volume 138, Issue 11 , 2016 ; 00220434 (ISSN) ; Behzadipour, S ; Salarieh, H ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
Abstract
A bilateral nonlinear adaptive impedance controller is proposed for the control of multi-degrees-of-freedom (DOF) teleoperation systems. In this controller, instead of conventional position and/or force tracking, the impedance of the nonlinear teleoperation system is controlled. The controller provides asymptotic tracking of two impedance models in Cartesian coordinates for the master and slave robots. The proposed bilateral controller can be used in different medical applications, such as telesurgery and telerehabilitation, where the impedance of the robot in interaction with human subject is of great importance. The parameters of the two impedance models can be adjusted according to the...
Mixed oxide nanotubes in nanomedicine: A dead-end or a bridge to the future?
, Article Ceramics International ; 2020 ; Nasiri Tabrizi, B ; Yeong, C. H ; Madaah Hosseini, H. R ; Saber Samandari, S ; Basirun, W. J ; Tsuzuki, T ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Nanomedicine has seen a significant rise in the development of new research tools and clinically functional devices. In this regard, significant advances and new commercial applications are expected in the pharmaceutical and orthopedic industries. For advanced orthopedic implant technologies, appropriate nanoscale surface modifications are highly effective strategies and are widely studied in the literature for improving implant performance. It is well-established that implants with nanotubular surfaces show a drastic improvement in new bone creation and gene expression compared to implants without nanotopography. Nevertheless, the scientific and clinical understanding of mixed oxide...
Mixed oxide nanotubes in nanomedicine: A dead-end or a bridge to the future?
, Article Ceramics International ; Volume 47, Issue 3 , 2021 , Pages 2917-2948 ; 02728842 (ISSN) ; Nasiri Tabrizi, B ; Yeong, C. H ; Madaah Hosseini, H. R ; Saber-Samandari, S ; Basirun, W. J ; Tsuzuki, T ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Nanomedicine has seen a significant rise in the development of new research tools and clinically functional devices. In this regard, significant advances and new commercial applications are expected in the pharmaceutical and orthopedic industries. For advanced orthopedic implant technologies, appropriate nanoscale surface modifications are highly effective strategies and are widely studied in the literature for improving implant performance. It is well-established that implants with nanotubular surfaces show a drastic improvement in new bone creation and gene expression compared to implants without nanotopography. Nevertheless, the scientific and clinical understanding of mixed oxide...
Bio-based UV curable polyurethane acrylate: Morphology and shape memory behaviors
, Article European Polymer Journal ; Volume 118 , 2019 , Pages 514-527 ; 00143057 (ISSN) ; Shojaei, A ; Sundararaj, U ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Smart bio-based shape memory polymers with high performance and fast response have the exciting potential to meet the growing need in biomedical applications. In this study, novel fast response UV-curable shape memory polyurethane acrylates (SMPUAs) comprising polycaprolactone diols (PCL-Diol), hexamethylene diisocyanate (HDI) and hydroxy-methyl methacrylate (HEMA) were synthesized by two-step bulk polymerization. Two series of PUAs with almost the same amount of hard segment content (HSC) were prepared with varying soft-segment molecular weight (2000, 3000, and 4000 g/mol) and different molar ratios of constituents. A mono-functional reactive diluent was used to control HSC and reduce the...
Nitinol spinal vertebrae: A favorable new substitute
, Article International Journal of Engineering, Transactions B: Applications ; Volume 32, Issue 6 , 2019 , Pages 842-851 ; 1728144X (ISSN) ; Parsafar, M ; Rashtiani, Y ; Jadidi, M ; Sharif University of Technology
Materials and Energy Research Center
2019
Abstract
Scoliosis, kyphosis, and bone fracture are health problems, especially of the elderly throughout the world. The vertebra protects the spinal cord. Any impairment to the vertebra can lead to pain and nervousness. NiTi alloy (Nitinol) helps to resolve the problem by fulfilling such requirements as for strength, durability, resistance to wear, and shockwave damping which is due to the shape memory effect. Nitinol medical applications have so far been restricted to surgical devices and orthopaedics. Little has been said about Nitinol use for medication of the spinal vertebra disorder. This article appraises the potential features of Nitinol for vertebral implantation and therapeutic prescription...
Improved adhesion of NiTi wire to silicone matrix for smart composite medical applications
, Article Materials and Design ; Volume 30, Issue 9 , 2009 , Pages 3667-3672 ; 02641275 (ISSN) ; Hassanzadeh Nemati, N ; Bagheri, R ; Sharif University of Technology
2009
Abstract
Recent uses of intelligent composites in biomedical appliances aggrandize the necessity of bonding-strength improvement in NiTi/silicone matrix interface. SEM micrographs and pull-out tests are employed to determine the strength of the NiTi/silicone bonds in a flexible composite piece. Greater adhesion strengths are obtained due to the presence of thin oxide layer, surface roughness and frictional forces between the embedded-wires and the contacting phase. Effect of curing treatment on phase transformation temperatures of the wires is determined by electrical resistivity (ER) measurements. Results show that the curing treatment shifts the transition points of the wires towards higher...
Polyvinyl alcohol and polyvinyl alcohol/ polyvinyl pyrrolidone biomedical foams crosslinked by gamma irradiation
, Article Journal of Cellular Plastics ; Volume 53, Issue 4 , 2017 , Pages 359-372 ; 0021955X (ISSN) ; Frounchi, M ; Dadbin, S ; Sharif University of Technology
SAGE Publications Ltd
2017
Abstract
Foams for biomedical applications were made from polyvinyl alcohol, polyvinyl alcohol / polyvinyl pyrrolidone blend and their nanocomposites with nanoclay by clean processes. Air was entrapped into the aqueous polymer solutions during vigorous mixing and then the solutions were freeze-dried. The foams structure was stabilized by crosslinking via gamma irradiation without using any harmful chemicals. The hydrophilic biocompatible foams possessed interconnected open cell structure with remarkable capacity to absorb and retain water. The foams in wet state were soft and flexible. Desirable pore structure and higher water absorption was obtained at a solution concentration of 5 wt% for both...
Stimuli-responsive chitosan as an advantageous platform for efficient delivery of bioactive agents
, Article Journal of Controlled Release ; Volume 317 , 2020 , Pages 216-231 ; Tavakolian, M ; Yazdani, H ; Frounchi, M ; van de Ven, T. G. M ; Maysinger, D ; Kakkar, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Despite a diverse range of active pharmaceutical agents currently at our disposal, high morbidity rate diseases continue to pose a major health crisis globally. One of the important parameters in this regard is the controlled cargo delivery at desired sites. Among a variety of synthetic and natural macromolecular systems, chitosan, an abundant biopolymer, offers a platform for tailored architectures that could have high loading capacity of cargo, target and deliver. Stimuli directed accumulation of vehicles and drug release is an area of direct relevance to biomedical applications. In this review, we highlight essential characteristics of modified chitosan that present themselves for...
Production of nanostructured Ni-Ti-Ag alloy by mechanical alloying
, Article Advanced Materials Research ; Vol. 829 , 2014 , pp. 67-72 ; ISSN: 10226680 ; Sadrnezhaad, S. K ; Bagheri, G. A ; Sharif University of Technology
Abstract
Because of corrosion resistance and antibacterial effects, shape memory Ni-Ti-Ag alloy can be considered for different biomedical applications. Mechanical alloying is used to produce nanostructured Ni-Ti-Ag alloy from elemental powders. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) are used to characterize the product. Results show that after 1h milling, homogenous distribution of the elements occurs; while no intermetallic compounds is observed. After 3h milling, titanium dissolves in nickel to form amorphous and nanostructured solid phases. Peaks of B2 phase appear in the XRD pattern after the 3h milling of the powder mixture. Sintering of the 3h-milled...
Electrophoretic encapsulation for slow release of vancomycin from perpendicular TiO2 nanotubes grown on Ti6Al4V electrodes
, Article Materials Research Express ; Volume 6, Issue 12 , 2019 ; 20531591 (ISSN) ; https://iopscience.iop.org/article/10.1088/2053-1591/ab6c98 ; Ahmadi Seyedkhani, S ; Sadrnezhaad, S. K ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
Ordered perpendicular TiO2 nanotubes (TNT) with 405 to 952 nm length and 60 to 90 nm diameter were grown via 40 to 120 min anodization of Ti6Al4V flat substrates. The samples were called TNT-40, -60, -80, -100, and -120. Vancomycin was loaded on the bare and anodized electrodes by separate immersion and electrophoretic (EP) deposition procedures. EP loading resulted in storage capacity of 5221.86 μg cm-2 for TNT-80 which was much higher than 1036.75 μg cm-2 of immersed sample. Drug release comprised of three stages: (i) burst release (78% for the bare, and 23% for the TNT-80 sample), (ii) gradual transport (21% for the bare, and 64% for the TNT-80 sample), and (iii) equilibrium. Transfer...
Electrophoretic encapsulation for slow release of vancomycin from perpendicular TiO2 nanotubes grown on Ti6Al4V electrodes
, Article Materials Research Express ; Volume 6, Issue 12 , 2019 ; 20531591 (ISSN) ; Ahmadi Seyedkhani, S ; Sadrnezhaad, S. K ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
Ordered perpendicular TiO2 nanotubes (TNT) with 405 to 952 nm length and 60 to 90 nm diameter were grown via 40 to 120 min anodization of Ti6Al4V flat substrates. The samples were called TNT-40, -60, -80, -100, and -120. Vancomycin was loaded on the bare and anodized electrodes by separate immersion and electrophoretic (EP) deposition procedures. EP loading resulted in storage capacity of 5221.86 μg cm-2 for TNT-80 which was much higher than 1036.75 μg cm-2 of immersed sample. Drug release comprised of three stages: (i) burst release (78% for the bare, and 23% for the TNT-80 sample), (ii) gradual transport (21% for the bare, and 64% for the TNT-80 sample), and (iii) equilibrium. Transfer...
Microfluidic-based multi-organ platforms for drug discovery
, Article Micromachines ; Volume 7, Issue 9 , 2016 ; 2072666X (ISSN) ; Khadem Mohtaram, N ; Pezeshgi Modarres, H ; Mohammadi, M. H ; Geraili, A ; Jafari, P ; Akbari, M ; Sanati Nezhad, A ; Sharif University of Technology
MDPI AG
Abstract
Development of predictive multi-organ models before implementing costly clinical trials is central for screening the toxicity, efficacy, and side effects of new therapeutic agents. Despite significant efforts that have been recently made to develop biomimetic in vitro tissue models, the clinical application of such platforms is still far from reality. Recent advances in physiologically-based pharmacokinetic and pharmacodynamic (PBPK-PD) modeling, micro- and nanotechnology, and in silico modeling have enabled single- and multi-organ platforms for investigation of new chemical agents and tissue-tissue interactions. This review provides an overview of the principles of designing...
Effective surface modification of MnFe2O4@SiO2@PMIDA magnetic nanoparticles for rapid and high-density antibody immobilization
, Article Applied Surface Science ; Volume 426 , 2017 , Pages 1023-1029 ; 01694332 (ISSN) ; Soleimani, M ; Ghahremanzadeh, R ; Vossoughi, M ; Esmaeili, E ; Sharif University of Technology
Abstract
The present study is aimed at the synthesis of MnFe2O4@SiO2@PMIDA in terms of highly efficient sensing platform for anti-prostate specific membrane antigen (PSMA) immobilization. Superparamagnetic manganese ferrite nanoparticles were synthesized following co-precipitation method and then SiO2 shell was coated on the magnetic core with tetraethyl orthosilicate (TEOS) through a silanization reaction to prevent oxidation, agglomeration and, increase the density of OH groups on the surface of MnFe2O4. Subsequently, MnFe2O4@SiO2@PMIDA obtained as a result of the reaction between N-(phosphonomethyl)iminodiacetic acid (PMIDA) and MnFe2O4@SiO2. The reactive carboxyl groups on the surface of magnetic...
2D MXene nanocomposites: electrochemical and biomedical applications
, Article Environmental Science: Nano ; Volume 9, Issue 11 , 2022 , Pages 4038-4068 ; 20518153 (ISSN) ; Nourmohammadi Khiarak, B ; Tao, R ; Wang, Z ; Ahmadi, S ; Hassanpour, M ; Rabiee, M ; Saeb, M. R ; Lima, E. C ; Rabiee, N ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
In recent years, key questions about the interaction of 2D MXene nanomaterials in electrochemical and biomedical applications have been raised. Most research has focused on clarifying the exclusive properties of the materials; however, only limited reports have described the biomedical applications of 2D nanomaterials. 2D MXenes are monolayer atomic nanosheets resulting from MAX phase ceramics. The hydrophilic properties, metallic conductivity, stability, and exclusive physiochemical performances make them promising materials for electrochemical and biomedical applications, including CO2 reduction, H2 evolution, energy conversion and storage, supercapacitors, stimuli-responsive drug delivery...
Enhancing glass ionomer cement features by using the HA/YSZ nanocomposite: A feed forward neural network modelling
, Article Journal of the Mechanical Behavior of Biomedical Materials ; Vol. 29 , January , 2014 , pp. 317-327 ; ISSN: 17516161 ; Salehi, S ; Nemati, A ; Tavakoli, R ; Solati Hashjin, M ; Sharif University of Technology
Abstract
Despite brilliant properties of glass ionomer cement (GIC), its weak mechanical property poses an obstacle for its use in medical applications. The present research aims to formulate hydroxyapatite/yttria-stabilized zirconia (HA/YSZ) in the composition of GIC to enhance mechanical properties and to improve fluoride release of GIC. HA/YSZ was synthesized via a sol-gel method and characterized by applying X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photo-emission spectroscopy (XPS) and simultaneous thermal analysis (STA) along with transmission electron microscopy (TEM) methods. The synthesized nanocomposite was mixed with GIC at a fixed composition of 5....