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    Electronic structure of some thymol derivatives correlated with the radical scavenging activity: Theoretical study

    , Article Food Chemistry ; Vol. 165, issue , Dec , 2014 , p. 451-459 Jebelli Javan, Ashkan ; Jebeli Javanb, M ; Sharif University of Technology
    Abstract
    Molecules acting as antioxidants capable of scavenging reactive oxygen species (ROS) are of upmost importance in the living cell. Thymol derivatives exhibit various antioxidant activities and potential health benefits. Exploration of structure-radical scavenging activity (SAR) was approached with a wide range of thymol derivatives. To accomplish this task, the DPPH experimental assay along with quantum-chemical calculations were also employed for these compounds. By comparing the structural properties of the derivatives of interest, their antioxidant activity was explained by the formation of an intramolecular hydrogen bond and the presence of unsaturated double bond (–CHdouble bond; length... 

    Antitumor effect of therapeutic HPV DNA vaccines with chitosan-based nanodelivery systems

    , Article Journal of Biomedical Science ; Vol. 21, issue. 1 , July , 2014 ; ISSN: 10217770 Tahamtan, A ; Ghaemi, A ; Gorji, A ; Kalhor, H. R ; Sajadian, A ; Tabarraei, A ; Moradi, A ; Atyabi, F ; Kelishadi, M ; Sharif University of Technology
    Abstract
    Cervical cancer is the second-most-common cause of malignancies in women worldwide, and the oncogenic activity of the human papilloma virus types (HPV) E7 protein has a crucial role in anogenital tumors. In this study, we have designed a therapeutic vaccine based on chitosan nanodelivery systems to deliver HPV-16 E7 DNA vaccine, considered as a tumor specific antigen for immunotherapy of HPV-associated cervical cancer. We have developed a Nano-chitosan (NCS) as a carrier system for intramuscular administration using a recombinant DNA vaccine expressing HPV-16 E7 (NCS-DNA E7 vaccine). NCS were characterized in vitro for their gene transfection ability. Results: The transfection of CS-pEGFP... 

    Chemometrics-assisted effect-directed analysis of crude and refined oil using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry

    , Article Environmental Science and Technology ; Vol. 48, issue. 5 , 2014 , pp. 3074-3083 ; ISSN: 0013936X Radovic, J. R ; Thomas, K. V ; Parastar, H ; Diez, S ; Tauler, R ; Bayona, J. M ; Sharif University of Technology
    Abstract
    An effect-directed analysis (EDA) of fresh and artificially weathered (evaporated, photooxidized) samples of North Sea crude oil and residual heavy fuel oil is presented. Aliphatic, aromatic, and polar oil fractions were tested for the presence of aryl hydrocarbon receptor (AhR) agonist and androgen receptor (AR) antagonist, demonstrating for the first time the AR antagonist effects in the aromatic and, to a lesser extent, polar fractions. An extension of the typical EDA strategy to include an N-way partial least-squares (N-PLS) model capable of relating the comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS) data set to the bioassay data... 

    Efficient bio-nano hybrid solar cells via purple membrane as sensitizer

    , Article BioNanoScience ; Vol. 4, issue. 1 , 2014 , pp. 71-77 ; ISSN: 21911630 Janfaza, S ; Molaeirad, A ; Mohamadpour, R ; Khayati, M ; Mehrvand, J ; Sharif University of Technology
    Abstract
    Bacteriorhodopsin is a heptahelical protein found in the purple membrane of Halobacterium salinarum. The performance of bacteriorhodopsin was evaluated as a sensitizer in dye-sensitized solar cells (DSSCs). Bacteriorhodopsin was efficiently immobilized on the titanium dioxide nanoparticles and then tested for its ability to convert solar radiation to electricity. The photovoltaic performance of DSSC based on the bacteriorhodopsin sensitizer has been examined. Under AM1.5 irradiation, a short-circuit current of 0.28 mA cm−2, open-circuit voltages of 0.51 V, fill factor of 0.62, and an overall energy conversion efficiency of 0.09 % are achieved employing platinum as a counter electrode. Carbon... 

    Light harvesting and photocurrent generation by nanostructured photoelectrodes sensitized with a photosynthetic pigment: A new application for microalgae

    , Article Bioresource Technology ; Volume 163 , July , 2014 , Pages 1-5 ; ISSN: 09608524 Mohammadpour, R ; Janfaza, S ; Abbaspour Aghdam, F ; Sharif University of Technology
    Abstract
    Here in this study, successful conversion of visible light into electricity has been achieved through utilizing microalgal pigments as a sensitizer of nanostructured photo-electrode of dye-sensitized solar cells (DSSCs). For the first time, photosynthetic pigments extracted from microalgae grown in wastewater is employed to imitate photosynthesis process in bio-molecule-sensitized solar cells. Two designs of photoanode were employed: 10μm nanoparticular TiO2 electrode and 20μm long self-ordered, vertically oriented nanotube arrays of titanium dioxide films. Microalgal photosynthetic pigments are loaded on nanostructured electrodes and their photovoltaic performances have been investigated.... 

    Three-dimensional simulation of urine concentrating mechanism in a functional unit of rat outer medulla. I. Model structure and base case results

    , Article Mathematical Biosciences ; Vol. 258 , 2014 , pp. 44-56 ; ISSN: 00255564 Sohrabi, S ; Saidi, M. S ; Saadatmand, M ; Banazadeh, M. H ; Firoozabadi, B ; Sharif University of Technology
    Abstract
    The urine formation and excretion system have long been of interest for mathematicians and physiologists to elucidate the obscurities within the process happens in renal tissue. In this study, a novel three-dimensional approach is utilized for modeling the urine concentrating mechanism in rat renal outer medulla which is essentially focused on demonstrating the significance of tubule's architecture revealed in anatomic studies and physiological literature. Since nephrons and vasculatures work interdependently through a highly structured arrangement in outer medulla which is dominated by vascular bundles, a detailed functional unit is proposed based on this specific configuration.... 

    Substrate oscillations boost recombinant protein release from Escherichia coli

    , Article Bioprocess and Biosystems Engineering ; Volume 37, Issue 5 , May , 2014 , Pages 881-890 ; ISSN: 16157591 Jazini, M ; Herwig, C ; Sharif University of Technology
    Abstract
    Intracellular production of recombinant proteins in prokaryotes necessitates subsequent disruption of cells for protein recovery. Since the cell disruption and subsequent purification steps largely contribute to the total production cost, scalable tools for protein release into the extracellular space is of utmost importance. Although there are several ways for enhancing protein release, changing culture conditions is rather a simple and scalable approach compared to, for example, molecular cell design. This contribution aimed at quantitatively studying process technological means to boost protein release of a periplasmatic recombinant protein (alkaline phosphatase) from E. coli.... 

    Simulation of blood oxygenation in capillary membrane oxygenators using modified sulfite solution

    , Article Biophysical Chemistry ; Vol. 195, issue , Dec , 2014 , p. 8-15 Tabesh, H ; Amoabediny, G ; Rasouli, A ; Ramedani, A ; Poorkhalil, A ; Kashefi, A ; Mottaghy, K ; Sharif University of Technology
    Abstract
    Blood oxygenation is the main performance characteristic of capillary membrane oxygenators (CMOs). Handling of natural blood in in vitro investigations of CMOs is quite complex and time-consuming. Since the conventional blood analog fluids (e.g. water/glycerol) lack a substance with an affinity to capture oxygen comparable to hemoglobin's affinity, in this study a novel approach using modified sulfite solution is proposed to address this challenge. The solution comprises sodium sulfite as a component, simulating the role of hemoglobin in blood oxygenation. This approach is validated by OTR (oxygen transfer rate) measured using native porcine blood, in two types of commercially available... 

    Optimization of culture medium and modeling of curdlan production from Paenibacillus polymyxa by RSM and ANN

    , Article International Journal of Biological Macromolecules ; Vol. 70, issue , Jul , 2014 , p. 463-473 Rafigh, S. M ; Yazdi, A. V ; Vossoughi, M ; Safekordi, A. A ; Ardjmand, M ; Sharif University of Technology
    Abstract
    Paenibacillus polymyxa ATCC 21830 was used for the production of curdlan gum for first time. A Box-Behnken experimental design was applied to optimize six variables of batch fermentation culture each at three levels. Statistical analyses were employed to investigate the direct and interactive effects of variables on curdlan production. Optimum cultural conditions were temperature (50. °C), pH (7), fermentation time (96. h), glucose (100. g/L), yeast extract (3. g/L) and agitation speed (150. rpm). The yield of curdlan production was 6.89. g/L at optimum condition medium. Response surface methodology (RSM) and artificial neural network (ANN) were used to model cultural conditions of curdlan... 

    Optimization of operating parameters and rate of uranium bioleaching from a low-grade ore

    , Article Journal of Radioanalytical and Nuclear Chemistry ; Vol. 301, issue. 2 , 2014 , pp. 341-350 ; ISSN: 02365731 Rashidi, A ; Roosta-Azad, R ; Safdari, S. J ; Sharif University of Technology
    Abstract
    In this study the bioleaching of a low-grade uranium ore containing 480 ppm uranium has been reported. The studies involved extraction of uranium using Acidithiobacillus ferrooxidans derived from the uranium mine samples. The maximum specific growth rate (μ max) and doubling time (t d) were obtained 0.08 h-1 and 8.66 h, respectively. Parameters such as Fe2+ concentration, particle size, temperature and pH were optimized. The effect of pulp density (PD) was also studied. Maximum uranium bio-dissolution of 100 ± 5 % was achieved under the conditions of pH 2.0, 5 % PD and 35 °C in 48 h with the particles of d 80 = 100 μm. The optimum concentration of supplementary Fe2+ was dependent to the PD.... 

    Disc size markedly influences concentration profiles of intravenously administered solutes in the intervertebral disc: A computational study on glucosamine as a model solute

    , Article European Spine Journal ; Vol. 23, issue. 4 , April , 2014 , p. 715-723 Motaghinasab, S ; Shirazi-Adl, A ; Parnianpour, M ; Urban, J. P. G ; Sharif University of Technology
    Abstract
    Purpose: Tests on animals of different species with large differences in intervertebral disc size are commonly used to investigate the therapeutic efficacy of intravenously injected solutes in the disc. We hypothesize that disc size markedly affects outcome. Methods: Here, using a small non-metabolized molecule, glucosamine (GL) as a model solute, we calculate the influence of disc size on transport of GL into rat, rabbit, dog and human discs for 10 h post intravenous-injection. We used transient finite element models and considered an identical GL supply for all animals. Results: Huge effects of disc size on GL concentration profiles were found. Post-injection GL concentration in the rat... 

    Statistical screening of medium components for recombinant production of Pseudomonas aeruginosa ATCC 9027 rhamnolipids by nonpathogenic cell factory pseudomonas putida KT2440

    , Article Molecular Biotechnology ; Vol. 56, issue. 2 , 2014 , p. 175-191 Setoodeh, P ; Jahanmiri, A ; Eslamloueyan, R ; Niazi, A ; Ayatollahi, S. S ; Aram, F ; Mahmoodi, M ; Hortamani, A ; Sharif University of Technology
    Abstract
    Rhamnolipids (RLs) produced by the opportunistic human pathogen Pseudomonas aeruginosa are considered as potential candidates for the next generation of surfactants. Large-scale production of RLs depends on progress in strain engineering, medium design, operating strategies, and purification procedures. In this work, the rhlAB genes extracted from a mono-RLs-producing strain of P. aeruginosa (ATCC 9027) were introduced to an appropriate safety host Pseudomonas putida KT2440. The capability of the recombinant strain was evaluated in various media. As a prerequisite for optimal medium design, a set of 32 experiments was performed in two steps for screening a number of macro-nutritional... 

    Plant hormones as signals in arbuscular mycorrhizal symbiosis

    , Article Critical Reviews in Biotechnology ; Vol. 34, issue. 2 , 2014 , p. 123-133 Miransari, M ; Abrishamchi, A ; Khoshbakht, K ; Niknam, V ; Sharif University of Technology
    Abstract
    Arbuscular mycorrhizal (AM) fungi are non-specific symbionts developing mutual and beneficial symbiosis with most terrestrial plants. Because of the obligatory nature of the symbiosis, the presence of the host plant during the onset and proceeding of symbiosis is necessary. However, AM fungal spores are able to germinate in the absence of the host plant. The fungi detect the presence of the host plant through some signal communications. Among the signal molecules, which can affect mycorrhizal symbiosis are plant hormones, which may positively or adversely affect the symbiosis. In this review article, some of the most recent findings regarding the signaling effects of plant hormones, on... 

    Two-compartment processing as a tool to boost recombinant protein production

    , Article Engineering in Life Sciences ; Vol. 14, issue. 2 , March , 2014 , p. 118-128 Jazini, M ; Herwig, C ; Sharif University of Technology
    Abstract
    Pichia pastoris is used extensively as a production platform for many recombinant proteins. The dissolved oxygen (DO) is one of the most important factors influencing protein production. The influence of the DO on productivity has not been studied independent from the feed rate. In this work, various DO levels were investigated independent from the feed rate. The model system was recombinant P. pastoris under the control of methanol-induced alcohol oxidase promoter, which expressed HRP as the target protein. No significant effect was observed in terms of titer and specific productivity, which is a confirmation of the fact that the DO in a one-compartment system cannot boost productivity for... 

    Effects of temperature shifts and oscillations on recombinant protein production expressed in Escherichia coli

    , Article Bioprocess and Biosystems Engineering ; Volume 36, Issue 11 , 2013 , Pages 1571-1577 ; 16157591 (ISSN) Jazini, M ; Herwig, C ; Sharif University of Technology
    2013
    Abstract
    Escherichia coli is widely used host for the intracellular expression of many proteins. However, in some cases also secretion of protein from periplasm was observed. Improvement of both intracellular and extracellular production of recombinant protein in E. coli is an attractive goal in order to reduce production cost and increase process efficiency and economics. Since heat shock proteins in E. coli were reported to be helpful for protein refolding and hindering aggregation, in this work different types of single and periodic heat shocks were tested on lab scale to enhance intracellular and extracellular protein production. A single heat shock prior to induction and different oscillatory... 

    Tissue growth into three-dimensional composite scaffolds with controlled micro-features and nanotopographical surfaces

    , Article Journal of Biomedical Materials Research - Part A ; Volume 101, Issue 10 , 2013 , Pages 2796-2807 ; 15493296 (ISSN) Tamjid, E ; Simchi, A ; Dunlop, J. W. C ; Fratzl, P ; Bagheri, R ; Vossoughi, M ; Sharif University of Technology
    2013
    Abstract
    Controlling topographic features at all length scales is of great importance for the interaction of cells with tissue regenerative materials. We utilized an indirect three-dimensional printing method to fabricate polymeric scaffolds with pre-defined and controlled external and internal architecture that had an interconnected structure with macro- (400-500 μm) and micro- (∼25 μm) porosity. Polycaprolactone (PCL) was used as model system to study the kinetics of tissue growth within porous scaffolds. The surface of the scaffolds was decorated with TiO2 and bioactive glass (BG) nanoparticles to the better match to nanoarchitecture of extracellular matrix (ECM). Micrometric BG particles were... 

    Optimal robust control of drug delivery in cancer chemotherapy: A comparison between three control approaches

    , Article Computer Methods and Programs in Biomedicine ; Volume 112, Issue 1 , 2013 , Pages 69-83 ; 01692607 (ISSN) Moradi, H ; Vossoughi, G ; Salarieh, H ; Sharif University of Technology
    2013
    Abstract
    During the drug delivery process in chemotherapy, both of the cancer cells and normal healthy cells may be killed. In this paper, three mathematical cell-kill models including log-kill hypothesis, Norton-Simon hypothesis and Emax hypothesis are considered. Three control approaches including optimal linear regulation, nonlinear optimal control based on variation of extremals and H∞-robust control based on μ-synthesis are developed. An appropriate cost function is defined such that the amount of required drug is minimized while the tumor volume is reduced. For the first time, performance of the system is investigated and compared for three control strategies; applied on three nonlinear models... 

    Preparation and evaluation of bioactive and compatible starch based superabsorbent for oral drug delivery systems

    , Article Journal of Drug Delivery Science and Technology ; Volume 23, Issue 5 , 2013 , Pages 511-517 ; 17732247 (ISSN) Pourjavadi, A ; Ebrahimi, A. A ; Barzegar, S ; Sharif University of Technology
    2013
    Abstract
    Novel types of highly swelling hydrogels (superabsorbent) were prepared by grafting crosslinked poly acrylic acid-co-2-hydroxyethylmetacrylate (PAA-co-HEMA) chains onto starch through a free radical polymerization method. The effect of grafting variables (i.e., concentration of methylenebisacrylamide (MBA), acrylic acid/2-hydroxy methymetacrylate (AA/HEMA) weight ratio, ammonium persulfate (APS), starch, neutralization percent, were systematically optimized to achieve a hydrogel with a maximum swelling capacity. The superabsorbent (SAP) formation was confirmed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The controlled-release behavior of... 

    Do the soft tissues located outside tibiofemoral joint have a role in bearing the compressive loads of the joint? An in-vitro study on sheep stifle joints

    , Article Gazzetta Medica Italiana Archivio per le Scienze Mediche ; Volume 172, Issue 7-8 , 2013 , Pages 595-601 ; 03933660 (ISSN) Hakkak, F ; Rostami, M ; Parnianpour, M ; Jabalameli, M ; Sharif University of Technology
    2013
    Abstract
    Aim. The compressive loads on the tibiofemoral joint are normally assumed to be borne solely via contact and pressing of the cartilage surfaces of tibia and femur. However, recent findings suggest that non-contact load-bearing mechanisms are active in the joint as well. In this context, a non-contact load-bearing mechanism involving soft tissue connections outside the tibiofemoral joint has been hypothesized as well. This paper addresses the validity of this hypothesis and the possible involvement of several soft tissue connections outside the joint. Methods. Sheep stifle (knee) joints were studied in vitro. The specimens were loaded in fixed displacement. Various soft tissues outside the... 

    Core flooding tests to investigate the effects of IFT reduction and wettability alteration on oil recovery during MEOR process in an Iranian oil reservoir

    , Article Applied Microbiology and Biotechnology ; Volume 97, Issue 13 , July , 2013 , Pages 5979-5991 ; 01757598 (ISSN) Rabiei, A ; Sharifinik, M ; Niazi, A ; Hashemi, A ; Ayatollahi, S ; Sharif University of Technology
    2013
    Abstract
    Microbial enhanced oil recovery (MEOR) refers to the process of using bacterial activities for more oil recovery from oil reservoirs mainly by interfacial tension reduction and wettability alteration mechanisms. Investigating the impact of these two mechanisms on enhanced oil recovery during MEOR process is the main objective of this work. Different analytical methods such as oil spreading and surface activity measurements were utilized to screen the biosurfactant-producing bacteria isolated from the brine of a specific oil reservoir located in the southwest of Iran. The isolates identified by 16S rDNA and biochemical analysis as Enterobacter cloacae (Persian Type Culture Collection (PTCC)...