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    Evaluating the toxic effect of an antimicrobial agent on single bacterial cells with optical tweezers

    , Article Biomedical Optics Express ; Volume 6, Issue 1 , 2015 , Pages 112-117 ; 21567085 (ISSN) Samadi, A ; Zhang, C ; Chen, J ; Reihani, S. N. S ; Chen, Z ; Sharif University of Technology
    OSA - The Optical Society  2015
    We implement an optical tweezers technique to assess the effects of chemical agents on single bacterial cells. As a proof of principle, the viability of a trapped Escherichia coli bacterium is determined by monitoring its flagellar motility in the presence of varying concentrations of ethyl alcohol. We show that the “killing time” of the bacterium can be effectively identified from the correlation statistics of the positional time series recorded from the trap, while direct quantification from the time series or associated power spectra is intractable. Our results, which minimize the lethal effects of bacterial photodamage, are consistent with previous reports of ethanol toxicity that used... 

    A new model of pressure propagation in human tissue in HIFU application

    , Article Acta Medica Mediterranea ; Volume 31, Issue 7 , 2015 , Pages 1501-1505 ; 03936384 (ISSN) Hajian, S. R ; Abbaspour Tehrani Fard, A ; Pouladian, M ; Hemmasi, G. R ; Sharif University of Technology
    A. CARBONE Editore  2015
    This project is a new pressure model for propagating pressure inside one or several tissues at the time of treatment with high intensity focus ultrasound (HIFU). Pressure's changes are converted to heat's changes in tissue and this is done oscillatory. When the treatment is done in deeper tissues, obtained heat can affect surficial tissues. This pressure effect also can enter surficial tissues. Amount of pressure and heat possible injury can be controlled and reduced through this mechanical modelling. In this model we have used three layers and pressure also is obtained within these three layers and is investigated averagely. Obtained tissue in this mood is kidney tissue and it is tried to... 

    Advances in skin regeneration: application of electrospun scaffolds

    , Article Advanced Healthcare Materials ; Volume 4, Issue 8 , 2015 , Pages 1114-1133 ; 21922640 (ISSN) Norouzi, M ; Boroujeni, S. M ; Omidvarkordshouli, N ; Soleimani, M ; Sharif University of Technology
    Wiley-VCH Verlag  2015
    The paucity of cellular and molecular signals essential for normal wound healing makes severe dermatological ulcers stubborn to heal. The novel strategies of skin regenerative treatments are focused on the development of biologically responsive scaffolds accompanied by cells and multiple biomolecules resembling structural and biochemical cues of the natural extracellular matrix (ECM). Electrospun nanofibrous scaffolds provide similar architecture to the ECM leading to enhancement of cell adhesion, proliferation, migration and neo tissue formation. This Review surveys the application of biocompatible natural, synthetic and composite polymers to fabricate electrospun scaffolds as skin... 

    Structural characterization of a rhamnolipid-type biosurfactant produced by Pseudomonas aeruginosa MR01: Enhancement of di-rhamnolipid proportion using gamma irradiation

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 81, Issue 2 , 2010 , Pages 397-405 ; 09277765 (ISSN) Lotfabad, T. B ; Abassi, H ; Ahmadkhaniha, R ; Roostaazad, R ; Masoomi, F ; Zahiri, H. S ; Ahmadian, G ; Vali, H ; Noghabi, K. A ; Sharif University of Technology
    We previously reported that MR01, an indigenous strain of Pseudomonas aeruginosa, was able to produce a rhamnolipid-type biosurfactant. Here, we attempted to define the structural properties of this natural product. The analysis of the extracted biosurfactant by thin-layer chromatography (TLC) revealed the presence of two compounds corresponding to those of authentic mono- and di-rhamnolipid. The identity of two structurally distinguished rhamnolipids was confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Liquid chromatography/mass spectrometry (LC/MS) of extracted biosurfactant revealed up to seventeen different rhamnolipid congeners. Further quantification showed... 

    Associations of primary and secondary organic aerosols with airway and systemic inflammation in an elderly panel cohort

    , Article Epidemiology ; Volume 21, Issue 6 , 2010 , Pages 892-902 ; 10443983 (ISSN) Delfino, R. J ; Staimer, N ; Tjoa, T ; Arhami, M ; Polidori, A ; Gillen, D. L ; George, S. C ; Shafer, M. M ; Schauer, J. J ; Sioutas, C ; Sharif University of Technology
    Background: Exposure-response information about particulate air-pollution constituents is needed to protect sensitive populations. Particulate matter <2.5 mm (PM 2.5) components may induce oxidative stress through reactive-oxygen-species generation, including primary organics from combustion sources and secondary organics from photochemically oxidized volatile organic compounds. We evaluated differences in airway versus systemic inflammatory responses to primary versus secondary organic particle components, particle size fractions, and the potential of particles to induce cellular production of reactive oxygen species. Methods: A total of 60 elderly subjects contributed up to 12 weekly... 

    Comparison of transplantation of bone marrow stromal cells (BMSC) and stem cell mobilization by granulocyte colony stimulating factor after traumatic brain injury in rat

    , Article Iranian Biomedical Journal ; Volume 14, Issue 4 , Oct , 2010 , Pages 142-149 ; 1028852X (ISSN) Bakhtiary, M ; Marzban, M ; Mehdizadeh, M ; Joghataei, M. T ; Khoei, S ; Pirhajati Mahabadi, V ; Laribi, B ; Tondar, M ; Moshkforoush, A ; Sharif University of Technology
    Background: Recent clinical studies of treating traumatic brain injury (TBI) with autologous adult stem cells led us to compare effect of intravenous injection of bone marrow mesenchymal stem cells (BMSC) and bone marrow hematopoietic stem cell mobilization, induced by granulocyte colony stimulating factor (G-CSF), in rats with a cortical compact device. Methods: Forty adult male Wistar rats were injured with controlled cortical impact device and divided randomly into four groups. The treatment groups were injected with 2 × 106 intravenous bone marrow stromal stem cell (n = 10) and also with subcutaneous G-CSF (n = 10) and sham-operation group (n = 10) received PBS and "bromodeoxyuridine... 

    Synthesis and cytotoxicity assessment of superparamagnetic iron-gold core-shell nanoparticles coated with polyglycerol

    , Article Journal of Colloid and Interface Science ; Volume 345, Issue 1 , 2010 , Pages 64-71 ; 00219797 (ISSN) Jafari, T ; Simchi, A ; Khakpash, N ; Sharif University of Technology
    Core-shell iron-gold (Fe@Au) nanoparticles were synthesized by a facile reverse micelle procedure and the effect of water to surfactant molar ratio (w) on the size, size distribution and magnetic properties of the nanoparticles was studied. MTT assay was utilized to evaluate the cell toxicity of the nanoparticles. To functionalize the particles for MRI imaging and targeted drug delivery, the particles were coated by polyglycerol through capping with thiol followed by polymerization of glycidol. The characteristics of the particles were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometere (VSM), UV-visible spectroscopy, and Fourier... 

    Modeling, simulation, and optimal initiation planning for needle insertion into the liver

    , Article Journal of Biomechanical Engineering ; Volume 132, Issue 4 , 2010 ; 01480731 (ISSN) Sharifi Sedeh, R ; Ahmadian, M. T ; Janabi Sharifi, F ; Sharif University of Technology
    Needle insertion simulation and planning systems (SPSs) will play an important role in diminishing inappropriate insertions into soft tissues and resultant complications. Difficulties in SPS development are due in large part to the computational requirements of the extensive calculations in finite element (FE) models of tissue. For clinical feasibility, the computational speed of SPSs must be improved. At the same time, a realistic model of tissue properties that reflects large and velocity-dependent deformations must be employed. The purpose of this study is to address the aforementioned difficulties by presenting a cost-effective SPS platform for needle insertions into the liver. The study... 

    Self-modeling curve resolution techniques applied to comparative analysis of volatile components of Iranian saffron from different regions

    , Article Analytica Chimica Acta ; Volume 662, Issue 2 , 2010 , Pages 143-154 ; 00032670 (ISSN) Jalali Heravi, M ; Parastar, H ; Ebrahimi Najafabadi, H ; Sharif University of Technology
    Volatile components of saffron from different regions of Iran were extracted by ultrasonic-assisted solvent extraction (USE) and were analyzed by gas chromatography-mass spectrometry (GC-MS). Self-modeling curve resolution (SMCR) was proposed for resolving the co-eluted GC-MS peak clusters into pure chromatograms and mass spectra. Multivariate curve resolution-objective function minimization (MCR-FMIN) and multivariate curve resolution-alternating least square (MCR-ALS) were successfully used for this purpose. The accuracy of the qualitative and quantitative results was improved considerably using SMCR techniques. Comparison of the results of saffron from different regions of Iran showed... 

    A simple and efficient total synthesis of (±)-danshexinkun A, a bioactive diterpenoid from Salvia miltiorrhiza

    , Article Tetrahedron Letters ; Volume 51, Issue 3 , 2010 , Pages 540-542 ; 00404039 (ISSN) Matloubi Moghaddam, F ; Moridi Farimani, M ; Sharif University of Technology
    An efficient 12-step route for the synthesis of the diterpenoid quinone (±)-danshexinkun A in 23% overall yield from the corresponding highly substituted stilbene using a photocyclization strategy is described  

    Investigation of the effect of high +Gz accelerations on human cardiac function

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 27 , 2013 , Pages 54-63 ; 17516161 (ISSN) Jamshidi, M ; Ahmadian, M. T ; Sharif University of Technology
    This study investigates the effect of body acceleration on human cardiac function. Finite element analysis is conducted to simulate geometrical and mechanical properties of human heart. Heart geometrical modeling in three-dimension is performed by segmentation of cardiac MRI images. The nonlinear mechanical behavior of myocardium is modeled by Mooney-Rivlin, Polynomial, Ogden and Yeoh hyperelastic material models. Stress-strain curves of myocardial tissue are obtained from experimental compression tests on bovine heart samples. The experimental results are employed for the evaluation of material coefficients by the nonlinear least squares method. Among hyperelastic models, the Yeoh model... 

    A new approach for the in vitro identification of the cytotoxicity of superparamagnetic iron oxide nanoparticles

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 75, Issue 1 , 2010 , Pages 300-309 ; 09277765 (ISSN) Mahmoudi, M ; Simchi, A ; Imani, M ; Shokrgozar, M. A ; Milani, A. S ; Häfeli, U. O ; Stroeve, P ; Sharif University of Technology
    Superparamagnetic iron oxide nanoparticles (SPIONs) are increasingly used in medical applications, such as targeting delivery and imaging. In the future, patients are more likely to be exposed to pharmaceutical products containing such particles. The study of toxicity of SPIONs has become of great importance in recent years, although the published data in this arena is limited. The aim of the present work is to investigate the cytotoxicity of SPIONs and the effect of the particles on the cell medium components. For this purpose, uncoated and polyvinyl alcohol (PVA) coated SPIONs with narrow size distribution were synthesized via a well-known coprecipitation method. The mouse fibroblast cell... 

    Biodesulfurization of dibenzothiophene by a newly isolated Rhodococcus erythropolis strain

    , Article Bioresource Technology ; Volume 101, Issue 3 , 2010 , Pages 1102-1105 ; 09608524 (ISSN) Davoodi Dehaghani, F ; Vosoughi, M ; Ziaee, A. A ; Sharif University of Technology
    A new dibenzothiophene (DBT) desulfurizing bacterium was isolated from oil-contaminated soils in Iran. HPLC analysis and PCR-based detection of the presence of the DBT desulfurization genes (dszA, dszB and dszC) indicate that this strain converts DBT to 2-hydroxybiphenyl (2-HBP) via the 4S pathway. The strain, identified as Rhodococcus erythropolis SHT87, can utilize DBT, dibenzothiophene sulfone, thiophene, 2-methylthiophene and dimethylsulfoxide as a sole sulfur source for growth at 30 °C. The maximum specific desulfurization activity of strain SHT87 resting cells in aqueous and biphasic organic-aqueous systems at 30 °C was determined to be 0.36 and 0.47 μmol 2-HBP min-1 (g dry cell)-1,... 

    Experimental study and thermodynamic modeling for determining the effect of non-polar solvent (hexane)/polar solvent (methanol) ratio and moisture content on the lipid extraction efficiency from Chlorella vulgaris

    , Article Bioresource Technology ; Volume 201 , 2016 , Pages 304-311 ; 09608524 (ISSN) Malekzadeh, M ; Abedini Najafabadi, H ; Hakim, M ; Feilizadeh, M ; Vossoughi, M ; Rashtchian, D ; Sharif University of Technology
    Elsevier Ltd 
    In this research, organic solvent composed of hexane and methanol was used for lipid extraction from dry and wet biomass of Chlorella vulgaris. The results indicated that lipid and fatty acid extraction yield was decreased by increasing the moisture content of biomass. However, the maximum extraction efficiency was attained by applying equivolume mixture of hexane and methanol for both dry and wet biomass. Thermodynamic modeling was employed to estimate the effect of hexane/methanol ratio and moisture content on fatty acid extraction yield. Hansen solubility parameter was used in adjusting the interaction parameters of the model, which led to decrease the number of tuning parameters from 6... 

    Microwave-assisted extraction and high-throughput monolithic-polymer-based micro-solid-phase extraction of organophosphorus, triazole, and organochlorine residues in apple

    , Article Journal of Separation Science ; Volume 39, Issue 3 , 2016 , Pages 576-583 ; 16159306 (ISSN) Bagheri, H ; Es Haghi, A ; Basiri Pour, F ; Sharif University of Technology
    Wiley-VCH Verlag 
    A high-throughput micro-solid-phase extraction device based on a 96-well plate was constructed and applied to the determination of pesticide residues in various apple samples. Butyl methacrylate and ethylene glycol dimethacrylate were copolymerized as a monolithic polymer and placed in the cylindrically shaped stainless-steel meshes of 96-micro-solid-phase extraction device and used as an extracting unit. Before the micro-solid-phase extraction, microwave-assisted extraction was employed to facilitate the transfer of the pesticide residues from the apple matrix to liquid media. Then, 1 mL of the aquatic samples was transferred into the 96-well plate and the 96-micro-solid-phase extraction... 

    Effects of short term and long term Extremely Low Frequency Magnetic Field on depressive disorder in mice: Involvement of nitric oxide pathway

    , Article Life Sciences ; Volume 146 , 2016 , Pages 52-57 ; 00243205 (ISSN) Madjid Ansari, A ; Farzam Pour, S ; Sadr, A ; Shekarchi, B ; Majid Zadeh, A. K ; Sharif University of Technology
    Elsevier Inc 
    Aims Previous reports on the possible effects of Extremely Low Frequency Magnetic Fields (ELF MF) on mood have been paradoxical in different settings while no study has yet been conducted on animal behavior. In addition, it was shown that ELF MF exposure makes an increase in brain nitric oxide level. Therefore, in the current study, we aimed to assess the possible effect(s) of ELF MF exposure on mice Forced Swimming Test (FST) and evaluate the probable role of the increased level of nitric oxide in the observed behavior. Main methods Male adult mice NMRI were recruited to investigate the short term and long term ELF MF exposure (0.5 mT and 50 Hz, single 2 h and 2 weeks 2 h a day). Locomotor... 

    Microfluidic systems for stem cell-based neural tissue engineering

    , Article Lab on a Chip - Miniaturisation for Chemistry and Biology ; Volume 16, Issue 14 , 2016 , Pages 2551-2571 ; 14730197 (ISSN) Karimi, M ; Bahrami, S ; Mirshekari, H ; Moosavi Basri, S. M ; Bakhshian Nik, A ; Aref, A. R ; Akbari, M ; Hamblin, M. R ; Sharif University of Technology
    Royal Society of Chemistry  2016
    Neural tissue engineering aims at developing novel approaches for the treatment of diseases of the nervous system, by providing a permissive environment for the growth and differentiation of neural cells. Three-dimensional (3D) cell culture systems provide a closer biomimetic environment, and promote better cell differentiation and improved cell function, than could be achieved by conventional two-dimensional (2D) culture systems. With the recent advances in the discovery and introduction of different types of stem cells for tissue engineering, microfluidic platforms have provided an improved microenvironment for the 3D-culture of stem cells. Microfluidic systems can provide more precise... 

    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) Karimi, M ; 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
    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... 

    Electrospinning of nanodiamond-modified polysaccharide nanofibers with physico-mechanical properties close to natural skins

    , Article Marine Drugs ; Volume 14, Issue 7 , 2016 ; 16603397 (ISSN) Mahdavi, M ; Mahmoudi, N ; Rezaie Anaran, F ; Simchi, A ; Sharif University of Technology
    MDPI AG 
    Electrospinning of biopolymers has gained significant interest for the fabrication of fibrous mats for potential applications in tissue engineering, particularly for wound dressing and skin regeneration. In this study, for the first time, we report successful electrospinning of chitosan-based biopolymers containing bacterial cellulous (33 wt %) and medical grade nanodiamonds (MND) (3 nm; up to 3 wt %). Morphological studies by scanning electron microscopy showed that long and uniform fibers with controllable diameters from 80 to 170 nm were prepared. Introducing diamond nanoparticles facilitated the electrospinning process with a decrease in the size of fibers. Fourier transform infrared... 

    Micromechanics and constitutive modeling of connective soft tissues

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 60 , 2016 , Pages 157-176 ; 17516161 (ISSN) Fallah, A ; Ahmadian, M. T ; Firozbakhsh, K ; Aghdam, M. M ; Sharif University of Technology
    Elsevier Ltd 
    In this paper, a micromechanical model for connective soft tissues based on the available histological evidences is developed. The proposed model constituents i.e. collagen fibers and ground matrix are considered as hyperelastic materials. The matrix material is assumed to be isotropic Neo-Hookean while the collagen fibers are considered to be transversely isotropic hyperelastic. In order to take into account the effects of tissue structure in lower scales on the macroscopic behavior of tissue, a strain energy density function (SEDF) is developed for collagen fibers based on tissue hierarchical structure. Macroscopic response and properties of tissue are obtained using the numerical...