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News Article | March 4, 2016
Site: www.materialstoday.com

A stretchy, rubber-like biomaterial based on alginate derived from seaweed could overcome the shortcomings of conventional polyurethanes, which are used in the repair of damaged or diseased cardiac and vascular tissue [Daemi et al., Biomaterials 84 (2016) 54]. Polyurethanes represent an important biomaterial but are not biodegradable, are derived from petroleum-based raw materials, and do not promote the adherence and growth of cells. So a team of researchers from Iran Polymer & Petrochemical Institute, Royan Institute, University of Science and Culture in Iran, University of the Basque Country, and Harvard Medical School has come up with a novel approach. “We used alginate as a green, easily available and low-cost polysaccharide and combined it chemically with polyurethane to obtain a novel bio-based supramolecular ionic polymeric network,” explains Mehdi Barikani of the Iran Polymer & Petrochemical Institute. The novel biomaterial, known as alginate-based supramolecular ionic polyurethane (or ASPU), has tunable mechanical properties that depend upon the amount of alginate. Unlike previously reported bio-elastomers, ASPU contains physical crosslinks instead of chemical ones between its constituent parts that make it much more biodegradable in physiological conditions. Even though ASPU is biodegradable, it is exceptionally strong and tough – showing up to ten times the tensile strength of most synthetic biodegradable polymers. In fact, its toughness (190 kJ/m3) and tensile strength (50 MPa) is comparable to that of human tendons, ligaments, and cartilage. The novel biomaterial is also self-healing, the researchers have found, and can rapidly recover almost completely after rupture. Barikani, Hossein Baharvand and their colleagues believe that the outstanding mechanical properties of ASPU are down to the alterations that alginate makes to the microstructure of the elastomer. The amorphous nature of alginate reduces the overall crystallinity of polyurethane, which is demonstrated by the increased transparency of the material. “All of the interesting features of this biodegradable elastomer, including tunable biodegradation and strange mechanical properties combined with fast self-healing, make it ideal for future tissue engineering applications,” says Baharvand of the Royan Institute. “In addition, this material is biocompatible and… shows a minimal immune response in physiological conditions.” The researchers believe that there are no major obstacles to the adoption of ASPU for tissue engineering since alginate is already approved by the FDA for some applications, all the raw materials are commercially available and cost effective, and synthesis is performed under mild conditions. “[We] expect that our biodegradable elastomers will result in new applications for tissue engineering of load-bearing tissues,” Baharvand told Materials Today. The biomaterial has been tested in animal models and the researchers hope to move onto human clinical trials in the near future.


Algergawy A.,Friedrich - Schiller University of Jena | Algergawy A.,Tanta University | Babalou S.,University of Science and Culture | Konig-Ries B.,Friedrich - Schiller University of Jena
CEUR Workshop Proceedings | Year: 2016

As ontologies are the backbone of the Semantic Web, they attract much attention from researchers and engineers in many domains. This results in an increasing number of ontologies and semantic web applications. The number and complexity of such ontologies makes it hard for developers of ontologies and tools to decide which ontologies to use and reuse. To simplify the problem, a modularization algorithm can be used to partition ontologies into sets of modules. In order to evaluate the quality of modularization, we propose a new evaluation metric that quantifies the goodness of ontology modularization. In particular, we investigate the ontology module homogeneity, which assesses module cohesion, and the ontology module heterogeneity, which appraises module coupling. The experimental results demonstrate that the proposed metric is effective.


Kamali S.,Ferdowsi University of Mashhad | Kamali S.,University of Science and Culture | Karimi J.,Ferdowsi University of Mashhad | Hosseini M.,Ferdowsi University of Mashhad | And 3 more authors.
Biocontrol Science and Technology | Year: 2013

Entomopathogenic nematodes (EPNs) from the families Steinernematidae and Hererorhabditidae are considered excellent biological control agents against many insects that damage the roots of crops. In a regional survey, native EPNs were isolated, and laboratory and greenhouse experiments were conducted to determine the infectivity of EPNs against the cucurbit fly, Dacus ciliatus Loew (Diptera: Tephritidae). Preliminary experiments showed high virulence by a native strain of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) and a commercial strain of Steinernema carpocapsae Weiser (Rhabditida: Steinernematidae). These two strains were employed for further analysis while another native species, Steinernema feltiae, was excluded due to low virulence. In laboratory experiments, larvae and adult flies were susceptible to nematode infection, but both nematode species induced low mortality on pupae. S. carpocapsae had a significantly lower LC50 value against larvae than H. bacteriophora in filter paper assays. Both species of EPNs were effective against adult flies but S. carpocapsae caused higher adult mortality. When EPN species were applied to naturally infested fruit (150 and 300 IJs/cm2), the mortality rates of D. ciliatus larvae were 28% for S. carpocapsae and 12% for H. bacteriophora. Both EPN strains successfully reproduced and emerged from larvae of D. ciliates. In a greenhouse experiment, H. bacteriophora and S. carpocapsae had similar effects on fly larvae. Higher rates of larval mortality were observed in sandy loam and sand soils than in clay loam. The efficacy of S. carpocapsae and H. bacteriophora was higher at 25 and 30°C than at 19°C. The results indicated that S. carpocapsae had the best potential as a biocontrol agent of D. ciliatus, based on its higher virulence and better ability to locate the fly larvae within infected fruits. © 2013 Taylor & Francis.


Dehshibi M.M.,Science and Research Branch | Alavi M.,University of Science and Culture | Shanbehzadeh J.,Kharazmi University
13th International Conference on Hybrid Intelligent Systems, HIS 2013 | Year: 2014

Viseme (Visual Phoneme) clustering and analysis in every language is among the most important preliminaries for conducting various multimedia researches as talking head, lip reading, lip synchronization and computer assisted pronunciation training applications. With respect to the fact that clustering and analyzing visemes are language dependent processes, we concentrated our research on Persian language, which indeed has suffered from lack of such study. In this paper, we used a hierarchical approach for clustering visemes in Persian language based on principal component analysis of a polynomial kernel matrix considering coarticulation effect. Having obtained feature vector of each phoneme, we applied unweighted pair group method with arithmetic mean to each projected viseme on constructed manifold. Then furthest neighbor of the weight value as a result of reconstruction is set as the criterion for comparing viseme dissimilarity. In order to indicate the robustness of the proposed algorithm, a set of experiments was conducted on Persian databases in which two syllables were examined. Comparing the results of the clustering algorithm with that of the perceptual test given by an expert proves a reasonable evaluation of the proposed algorithm. © 2013 IEEE.


Fonoudi H.,Royan Institute for Stem Cell Biology and Technology | Fonoudi H.,Victor Chang Cardiac Research Institute | Fonoudi H.,University of New South Wales | Fonoudi H.,University of Tehran | And 14 more authors.
Journal of Visualized Experiments | Year: 2016

Maximizing the benefit of human pluripotent stem cells (hPSCs) for research, disease modeling, pharmaceutical and clinical applications requires robust methods for the large-scale production of functional cell types, including cardiomyocytes. Here we demonstrate that the temporal manipulation of WNT, TGF-β, and SHH signaling pathways leads to highly efficient cardiomyocyte differentiation of single-cell passaged hPSC lines in both static suspension and stirred suspension bioreactor systems. Employing this strategy resulted in ~ 100% beating spheroids, consistently containing > 80% cardiac troponin T-positive cells after 15 days of culture, validated in multiple hPSC lines. We also report on a variation of this protocol for use with cell lines not currently adapted to single-cell passaging, the success of which has been verified in 42 hPSC lines. Cardiomyocytes generated using these protocols express lineage-specific markers and show expected electrophysiological functionalities. Our protocol presents a simple, efficient and robust platform for the large-scale production of human cardiomyocytes. © 2016 Journal of Visualized Experiments.


Dehshibi M.M.,Science and Research Branch | Shanbezadeh J.,Kharazmi University | Alavi M.,University of Science and Culture
Proceedings of the 2012 12th International Conference on Hybrid Intelligent Systems, HIS 2012 | Year: 2012

Facial image analysis is one of the areas that have been received considerable attention in recent decades. In addition to areas such as face recognition, gender classification, emotion recognition, and age estimation, there are new applications that have not been studied yet. Family similarity recognition is a new trend that has been studied in this paper for the first time. Local Gabor Binary Pattern Histogram Sequence (LGBPHS) has led to many important advances in face recognition, including over looking generalizability and training issues. Given the current status of this study, two approaches were considered: (1) holistic approach and (2) component-based approach, which embodies the practical principles of theory. In order to model facial family manifold, LGBP is used both for the holistic view and components of the face. For recognition, histogram intersection is used to measure the similarity of different LGBPHSes and the nearest neighborhood is exploited for final clustering. In order to prove the efficiency of the proposed method three set of experiments are conducted in which both subjective and algorithmic issues are considered. It is observed in the course of experiments that the proposed method outperforms the subjective test up to 15%, and outperforms the observed state of the art face recognition methods up to 25.06%. © 2012 IEEE.


Hadadinejad M.,University of Agriculture Science | Salim Pour A.,University of Science and Culture | Nosrati S.Z.,Academic Center for Education | Nosrati S.Z.,University of Tehran | And 2 more authors.
Vitis - Journal of Grapevine Research | Year: 2014

Grapes are an important horticultural crop that is popularly consumed in a variety of different forms; the fruit is eaten in at its immature stage, as ripe fruit and dried as raisins and vine leaves are also consumed. Therefore any research on ways to improve production of Iranian grapes in terms of quality and quantity is valuable. The main purpose of this study was to test the use of Phenyl Phetalamic Acid (PPA) to improve fruit set and quality. The experiment was designed as a factorial for four grapevine cultivars; 'Razeghi', 'Askari', 'Sefidaly' and 'Rishbaba' and three concentrations of PPA(0,500,1000 mg-L -1). Treatments were arranged in a completely randomized design with three replications. The experiment was done in the Kashmar vineyard (Khorasan Razavi province) during 2010 spring. PPA treatment was applied by foliar spraying at the stage of 50 % anthesis. Results showed that PPA levels had a significant effect on evaluated cluster traits (weight, length and number) and berry (number, weight, length and diameter). Fruit set index (number of berries per cluster) was 263.11 for 'Sefidaly' followed by 113,109.89 and 76.11 for 'Askari', 'Razeghi' and 'Rishbaba', respectively. 'Askari' and 'Razeghi' cultivars showed similar and insignificant reactions but their difference was significant compared to 'Rishbaba'. The effect was significant for interactions of traits for cluster, berry and seed except for number of berries per cluster. Based on these results, cluster characters were significantly and positively affected by PPA treatment at the concentration of 1000 mg-L-1. This concentration increased fruit set by 26.2 % compared to the control in all cultivars except for Askari. The PPA concentration 500 mg-L-1, observed as the most effective treatment for improved berry characters, provided its non-significant difference with 1000 mg-L-1. Seed number per berry decreased significantly in 'Askari' and 'Rishbaba' at 500 mg-L -1, which was considered positive in terms of quality. In summary, results determined that PPA had a positive effect on fruit as an auxin synergist. These improved berry characteristics are hypothesized to occur through a decrease in the dominance of apical buds that would allow more metabolites to be directed to development of fruit clusters, although further research is required.


Gholami T.,University of Science and Culture | Ghadamyari M.,Guilan University | Oliaee A.O.,University of Science and Culture | Ajamhasani M.,University of Shahrood
Journal of Plant Protection Research | Year: 2013

The rosaceous branch borer, Ospheranteria coerulescens, is an important pest of rosaceous trees. This insect feeds on the twigs and branches of living trees and causes their death. The characterization of the insect phenoloxidase (PO) is of interest when doing comparative investigations, and so that we may be able to understand its biochemical properties. When designing new methods of insect control such as the use of PO inhibitors, an understanding of the biochemical properties is fundamental. In this study, PO from hemolymph of the rosaceous branch borer was purified using ammonium sulfate precipitation, gel-filtration, and ion-exchange chromatography. The biochemical properties were characterized using l-dihydroxyphenylalanine (L-DOPA) as the specific substrate. The apparent molecular weights of the three isoforms of PO were determined by SDS-PAGE to be 85.23, 79.45, and 66.06 kDa. Optimal pH for PO activity was pH 8, and the optimal temperature was 45°C. Phenoloxidase lost less than 50% of its relative activity after a 60 min incubation at the optimal temperature. The effects of ions and chemical materials such as K+, Ba2+, Zn2+ and EDTA on PO showed that PO activity was strongly inhibited by Zn2+. The Michaelis constant (Km) and maximum velocity (Vmax) were 88.61 mM and 0.14 μmol/min, respectively. The inhibitory effects of kojic acid, 4-hexylresorsinol, and quercetin on PO were determined, and the IC50s (inhibitory concentration) were estimated as 23.31 for kojic acid, 35.75 for 4-hexylresorcinol, and 60.8 μM for quercetin. The inhibitory potency of kojic acid was 1.54 times higher than that of 4-hexylresorcinol and 2.58 times higher than that of quercetin. Phenoloxidase was effectively inhibited by 4-hexylresorcinol, and the inhibition type was competitive. The inhibition types of PO by kojic acid and quercetin were found to be mixed.


Esmaeili-Choobar N.,Islamic Azad University at Tabriz | Esmaeili-Falak M.,Islamic Azad University at Tabriz | Roohi-Hir M.,Islamic Azad University at Tabriz | Keshtzad S.,University of science and culture
Electronic Journal of Geotechnical Engineering | Year: 2013

mechanisms, identified as soils of great importance. In contrast to the previous imaginations, presence of collapsible soils is not limited to dry climates, but they are likely present all over the earth. Because of increase in water content and due to engineering constructions under a constant stress, these soils can experience considerable settlements. In this research collapsibility potential of soils in Talesh (a county in northern Iran) has been evaluated. Assessment of collapsibility potential of under consideration soils has been done using experimental criteria and the standard based on double consolidation test (ASTM D 5333- 03). Results from these investigations show that soils in some areas have average to high collapsibility potentials. Also the importance of various parameters on collapsible potential has been investigated. © 2013, EJGE.


Harati M.,University of Science and Culture | Sabet A.H.,Islamic Azad University at Bandar Anzali | Modaraei A.H.,Islamic Azad University at Bandar Anzali
Journal of Engineering and Applied Sciences | Year: 2016

Past severe earthquakes such as Bam earthquake of 2003 and Tabas earthquake of 1978 have demonstrated that many cities in Iran are prone to be struck by near-fault earthquakes. Such earthquakes are impulsive in nature and therefore, they are more destructive than the ordinary ground shaking. In the 4th edition of Iranian Seismic Code (Standard No. 2800), some changes including a modification factor for the Elastic Acceleration Response Spectrum (EARS) have been recently recommended to reflect the effects of such probable near-fault earthquakes for the designing procedure. In this study, a numbers of 2D RC Moment Resisting Frames (MRFs) from 4-12 story buildings are designed linearly based on Iranian National Building Code (USTBC) and Standard No. 2800 as well. Subsequently their nonlinear models are reproduced for conducting Non-linear Dynamic Time History (NDTH) analysis. For this purpose, twenty impulsive ground motions are selected and scaled to be compatible with the Designed Based Earthquake (DBE) spectrum of the above mentioned code. It is concluded that the seismic performance of the analyzed structures are not satisfactory at all; no buildings are successful to satisfy the Life Safety (LS) performance level posed by guidelines such as ASCE41-06 or ASCE41-13. Moreover, it is worth mentioning that even Collapse Prevention (CP) limit states are not also met in some cases. Therefore, the recently added modifications in the Standard No. 2800 may be inadequate to incorporatethe near-fault earthquakes' effects. At the end some recommendations are addressed for the design of structures built in the regions vulnerable to be attacked by near-fault earthquakes. © Medwell Journals, 2016.

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