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Fabrication and Characterization of Nanocomposite Bone Scaffold with Gradient Structure Based on Thermoplastic Starch
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
Tissue regeneration by bio-compatible/degradable scaffolds is one of the widely used approaches in the field of tissue engineering. In this study, a thermoplastic starch based nanocomposite scaffold with gradient structure was fabricated by unidirectional freeze drying method. To increase the stability of the scaffold in the aqueous media, PVA was added to starch solution. Then, the PVA and starch molecules were cross-linked by adding citric acid to the mixture. On the one hand, to improve the mechanical properties of the scaffold, and control its bio-degradability on the other, cellulose nano-fibers were employed. Also, the bioactivity of the scaffold was induced by using hydroxyapatite...
Fabrication and characterization of a starch-based nanocomposite scaffold with highly porous and gradient structure for bone tissue engineering
, Article Biomedical Physics and Engineering Express ; Volume 4, Issue 5 , 2018 ; 20571976 (ISSN) ; Eslamian, M ; Bagheri, R ; Sharif University of Technology
Institute of Physics Publishing
2018
Abstract
Starch based scaffolds are considered as promising biomaterials for bone tissue engineering. In this study, a highly porous starch/polyvinyl alcohol (PVA) based nanocomposite scaffold with a gradient pore structure was made by incorporating different bio-additives, including citric acid, cellulose nanofibers, and hydroxyapatite (HA) nanoparticles. The scaffold was prepared by employing unidirectional and cryogenic freeze-casting and subsequently freeze-drying methods. Fourier transform infrared (FTIR) spectroscopy confirmed the cross-linking of starch and PVA molecules through multiple esterification phenomenon in the presence of citric acid as a cross-linking agent. Field emission scanning...
Investigation of hydrogen sensing properties and aging effects of Schottky like Pd/porous Si
, Article Journal of Sensors and Actuators B: Chemical ; Volume 146, Issue 1 , 8 April , 2010 , PP. 53–60 ; Iraji Zad, A. (Azam) ; Rahimi, F. (Fereshteh) ; Sharif University of Technology
2010
Abstract
We prepared porous silicon samples coated by continuous palladium layer in electroless process. Scanning electron microscopy (SEM) showed cauliflower-shape Pd clusters on the surface. I–V curves of Schottky like Pd/porous Si samples were measured in air and in hydrogen. These measurements showed a metal–interface–semiconductor configuration rather than an ideal Schottky diode. Variations of the electrical current in the presence of diluted hydrogen at room temperature revealed that the samples can sense hydrogen in a wide range of concentration (100–40,000 ppm) without any saturation behavior. Hydrogen sensing properties of these samples were investigated at room temperature for a duration...
Investigation and Analysis in Social Media Data and Cryptocurrency Bubble Fluctuations
, M.Sc. Thesis Sharif University of Technology ; Fatahi Valilai, Omid (Supervisor) ; Haji, Alireza (Supervisor) ; Beigi, Hamid (Co-Supervisor)
Abstract
Behavioral economics demonstrates that the sentiment can affect the behaviors and financial decisions of people. Can this be generalized to societies? For instance, is it possible for societies to experience emotions that will change their ways of decision making? This thesis attempts to perform an experiment addressing these questions. Bitcoin has been facing a transient phase of price volatilities. Many articles believe that bitcoin does not have an inherent value and is only derived by factors like the perception and acceptance of it and the sentiments among the investors. Digital currencies provide the unique possibility of measuring socioeconomic signals using digital traces.The...
PH-Sensitive stimulus-responsive nanocarriers for targeted delivery of therapeutic agents
, Article Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology ; Volume 8, Issue 5 , 2016 , Pages 696-716 ; 19395116 (ISSN) ; Eslami, M ; Sahandi Zangabad, P ; Mirab, F ; Farajisafiloo, N ; Shafaei, Z ; Ghosh, D ; Bozorgomid, M ; Dashkhaneh, F ; Hamblin, M. R ; Sharif University of Technology
Wiley-Blackwell
2016
Abstract
In recent years miscellaneous smart micro/nanosystems that respond to various exogenous/endogenous stimuli including temperature, magnetic/electric field, mechanical force, ultrasound/light irradiation, redox potentials, and biomolecule concentration have been developed for targeted delivery and release of encapsulated therapeutic agents such as drugs, genes, proteins, and metal ions specifically at their required site of action. Owing to physiological differences between malignant and normal cells, or between tumors and normal tissues, pH-sensitive nanosystems represent promising smart delivery vehicles for transport and delivery of anticancer agents. Furthermore, pH-sensitive systems...