Aflatoxin M1 Contamination Levels in Cheeses Sold in Isfahan Province, Iran

Ali Sharifzadeh,Payam Ghasemi-Dehkordi,Mohsen Foroughi,Elham Mardanpour-Shahrekordi,Shahin Ramazi 질병관리본부 2017 Osong Public Health and Research Persptectives Vol.8 No.4

Objectives: Aflatoxin M1 (AFM1)-contaminated dairy products pose serious human health risks, causing liver and renal failure if consumed. They are also related to decreased milk and egg production in infected animals. This study investigated the AFM1 contamination levels in cheeses sold in Isfahan province, Iran, by enzyme-linked immunosorbent assay (ELISA). Methods: A total of 100 white cheese samples were randomly collected from supermarkets in Isfahan province and after extraction using dichloromethane were prepared for the ELISA. Results: Of the 100 samples, 52 (52%) were contaminated by AFM1, at levels ranging from 50.2 to 424.4 ng/kg. The remaining 48% of the samples had undetectable AFM1 levels (< 50 ng/ kg). Based on the standard limit set by the European Commission and Iran, 8% (8/100) of the AFM1-positive samples (with concentrations between 250.2 and 424.4 ng/kg) had levels higher than the permissible value of 250 ng/kg. Conclusion: Although the percentage of cheese samples in Isfahan province with AFM1 levels exceeding the national permissible limit was low, the examination of cheeses and the milk used for their production is nevertheless important for ensuring public health. Furthermore, optimum storage conditions of animal feed should be ensured, and livestock nutrition must be monitored for the presence of AFM1 and other aflatoxins.

Evaluation of Microbial Contamination and Chemical Qualities of Cream-filled Pastries in Confectioneries of Chaharmahal Va Bakhtiari Province (Southwestern Iran)

Ali Sharifzadeh,Mohammad Hajsharifi-Shahreza,Payam Ghasemi-Dehkordi 질병관리본부 2016 Osong Public Health and Research Persptectives Vol.7 No.6

Objectives: High consumption of bakery products such as cream-filled pastries may cause serious health risks and food poisoning to humans. Therefore, investigation of the microbial and chemical qualities of bakery products containing cream is necessary. The purpose of the present study was to investigate the chemical qualities and microbial contaminations of cream-filled pastries collected from confectioneries located in six cities in Chaharmahal Va Bakhtiari province (Southwestern Iran). Methods: Microbial tests and chemical characteristics (fat and acidity level) were done on 228 cream-filled pastries samples that were collected randomly from various confectioneries. Results: After microbial tests, it was found that 33.33% of all samples were contaminated by microbial agents. The microbial tests showed that Shahrekord (10.09%) and Broujen (9.21%) cities had high levels of contamination and in Koohrang (1.31%) it was low compared with the other four cities. High contamination of coliforms (61.84%), staphylococci (48.68%), and yeast (27.63%) were observed in almost all samples. The chemical analysis showed maximum amounts of fat content and titratable acidity in cream-filled pastry samples obtained from Lordegan and Shahrekord cities, respectively. Conclusion: The findings of the present work demonstrated that the microbial contamination and chemical quality of cream-filled pastries produced in confectionaries of Chaharmahal Va Bakhtiari province were not in acceptable ranges. These problems may be related to fecal contamination of cream samples or lack of hygiene by handlers and it is necessary to observe the standards of hygiene and to develop safe food handling techniques and aseptic pastry manufacturing systems in some confectioneries of Chaharmahal Va Bakhtiari province.

Time-dependent mathematical modeling of binary gas mixture in facilitated transport membranes (FTMs): A real condition for single-reaction mechanism

Mohammad Mehdi Moftakhari Sharifzadeh,Abtin Ebadi Amooghin,Mona Zamani Pedram,Mohammad Reza Omidkhah 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.39 No.-

In this study, a comprehensive time-dependent mathematical model for gas separation through thefacilitated transport membranes (FTMs) is presented. The model results have been validated withindependent CO2/N2 binary gas mixture experiments in DEA-impregnated PVA membranes. In theproposed model, non-equal diffusion coefficients of the carrier/complex and equilibrium constant for thechemical reaction kinetics between the carrier/permeant in the FTM have been considered. In addition, amethod to compute the diffusion coefficients, which depend on the concentration of each component inthe FTM, is presented. Moreover, effect of carrier concentration, feed partial pressure, kinetics ofreversible chemical reactions and membrane performances depending on operating condition have beenanalyzed. Owing to accurate calculation of physical–chemical parameter involved, this model is muchmore executive comparing to previous works. In addition, the real condition of the reaction kinetics andinfluencing of diffusion parameters of the components in FTMs, have been investigated. The predictedselectivity and permeability revealed good conformity with experimental data; with standard deviation(SD) 8.57% and 12.87%, respectively. In conclusion, this model with significant validity would bepredictive in cases for the entire range of diffusion-limit to a chemical-limit regime where theexperimental data, geometry condition, physical–chemical property of parameters is not available.

Evaluation of the hydraulic aperture of a rock joint using wavelet theory

Ahmad Mehrishal,M. Sharifzadeh 한국자원공학회 2013 Geosystem engineering Vol.16 No.1

Both mechanical and hydraulic behaviors of rock joints are closely dependent on joint aperture. Understanding how fracture wall roughness affects the fluid flow is important when modeling many subsurface problems. In this paper, a new evaluation method of joint hydraulic aperture using surface asperities height was developed, and the value of hydraulic aperture under different shear displacements was determined using the multi-scale wave decomposition method based on the wavelet theory and some statistical indices. For this purpose, a high-resolution laser scanning system was applied. The numerical simulations were based on the experimental data obtained by Sharifzadeh, Mitani, Esaki, and Urakawa (2004. Development of evaluation method of rock joint aperture distribution. EUROCK & 53 Geomechanics Colloquium) from a series of hydromechanical shear tests on natural granite rock joints. Using this method, the hydraulic aperture of joint surfaces has been developed for different shear steps to model the fluid flow of rock joints. The modeling procedure of mechanical aperture (or dilation) was precise and reliable. In addition, the proposed procedure appropriately estimated both hydraulic aperture and fluid flow rate. The conformity in the results of modeling and laboratory tests satisfactorily indicated the success of the proposed procedure.

Shear Model Development of Limestone Joints with Incorporating Variations of Basic Friction Coefficient and Roughness Components During Shearing

Mehrishal, S.,Sharifzadeh, M.,Shahriar, K.,Song, J. J. Springer Science + Business Media 2017 Rock mechanics and rock engineering Vol.50 No.4

<P>In relation to the shearing of rock joints, the precise and continuous evaluation of asperity interlocking, dilation, and basic friction properties has been the most important task in the modeling of shear strength. In this paper, in order to investigate these controlling factors, two types of limestone joint samples were prepared and CNL direct shear tests were performed on these joints under various shear conditions. One set of samples were travertine and another were onyx marble with slickensided surfaces, surfaces ground to #80, and rough surfaces were tested. Direct shear experiments conducted on slickensided and ground surfaces of limestone indicated that by increasing the applied normal stress, under different shearing rates, the basic friction coefficient decreased. Moreover, in the shear tests under constant normal stress and shearing rate, the basic friction coefficient remained constant for the different contact sizes. The second series of direct shear experiments in this research was conducted on tension joint samples to evaluate the effect of surface roughness on the shear behavior of the rough joints. This paper deals with the dilation and roughness interlocking using a method that characterizes the surface roughness of the joint based on a fundamental combined surface roughness concept. The application of stress-dependent basic friction and quantitative roughness parameters in the continuous modeling of the shear behavior of rock joints is an important aspect of this research.</P>

Size-dependent compressive strength properties of hard rocks and rock-like cementitious brittle materials

Mohammad Darbor,Faramarzi, Lohrasb,Sharifzadeh, Mostafa 한국자원공학회 2019 Geosystem engineering Vol.22 No.4

Rock engineering projects have always been constructed on different (from micro to macro) scales. This makes understanding rock behaviour at different scales essential. In previous statistical studies on igneous hard rocks, the correlation of uniaxial compressive strength (UCS) values in different diameters with estimations of specimen size effect models was weak. In view of this knowledge gap, the present research proposed a model of appropriate size effect in igneous hard rocks. This research also aimed at discussing the effect of specimen size and grain size on the UCS of concrete specimens. To achieve these aims, studies were conducted in parallel on the previous and new experimental data. Non-linear regression analysis on igneous hard rocks indicated that there is a better agreement between the outputs of the multi-fractal scaling model and the specimen size effect model using the fracture energy theory and the results of previous laboratory tests. In addition, in the experimental study, the grain size effect on the predictions of specimen size effect models was exhibited. The results of this research can be used for designing engineering projects at different scales.

Design of Novel 3D-Scaffold as a Potential Material to Induct Epidermal-Dermal Keratinocytes of Human-Adipose-Derived Stem Cells and Promote Fibroblast Cells Proliferation for Skin Regeneration

Azadeh Izadyari Aghmiuni,Mazyar Sharifzadeh Baei,Saeed Heidari Keshel,Azim Akbarzadeh Khiyavi 한국섬유공학회 2020 Fibers and polymers Vol.21 No.1

Dermal lesions and chronic wounds associated with burns or some diseases like diabetes are the more importantpublic health concerns which can affect the quality of life. Currently, tissue engineering is considered as the most effectivetherapeutic method although the design of polymeric substrates for epidermal-dermal differentiation and wound healing(scar-free) is the main challenge. For this purpose, we designed a hybrid three-dimensional scaffold (CPCP) based oncollagen/chitosan modified by PEG/PCL composite that can imitate differentiation pattern of both epidermis/dermis cells, viamimicking the structure and function of human skin. The physicochemical, mechanical and biological properties of designedscaffolds were evaluated to study their function for skin tissue engineering applications. Comparison of FTIR analysisshowed a chemical similarity between CPCP and decellularized dermal matrix (DDM). Our results showed that combinationof two natural/two synthetic polymers led to the formation of stronger 3D-network together with higher modulus (~18), waterabsorption (4-fold), porosity (~92) and consequently lower pores size (~54 μm), compared to natural, synthetic and natural/synthetic copolymer-based scaffolds. The observation of human skin fibroblast cells proliferation and morphology showedthat CPCP was more beneficial to cell adhesion, proliferation, and extension than that of other designed scaffolds due to itshydrophilicity and higher wettability (WCA=60 o). According to the results of RT-PCR, the more expression of epidermaldermalkeratinocytes induced by human-adipose-derived stem cells was observed on the CPCP along with a pattern similar toskin. The results demonstrate CPCP can act as a super-absorbent substrate/dressing for continuous absorption of woundexudates. Furthermore, it can potentially be effective for re-epithelialization of skin together with its derivative (hair follicles,sebaceous/sweat glands). This study indicates new insights into the design of skin- engineered scaffolds.

Validation of 3D discrete fracture network model focusing on areal sampling methods-a case study on the powerhouse cavern of Rudbar Lorestan pumped storage power plant, Iran

Bandpey, Abbas Kamali,Shahriar, Kourush,Sharifzadeh, Mostafa,Marefvand, Parviz Techno-Press 2018 Geomechanics & engineering Vol.16 No.1

Discontinuities considerably affect the mechanical and hydraulic properties of rock mass. These properties of the rock mass are influenced by the geometry of the discontinuities to a great extent. This paper aims to render an account of the geometrical parameters of several discontinuity sets related to the surrounding rock mass of Rudbar Lorestan Pumped Storage Power Plant powerhouse cavern making use of the linear and areal (circular and rectangular) sampling methods. Taking into consideration quite a large quantity of scanline and the window samplings used in this research, it was realized that the areal sampling methods are more time consuming and cost-effective than the linear methods. Having corrected the biases of the geometrical properties of the discontinuities, density (areal and volumetric) as well as the linear, areal and volumetric intensity accompanied by the other properties related to four sets of discontinuities were computed. There is an acceptable difference among the mean trace lengths measured using two linear and areal methods for the two joint sets. A 3D discrete fracture network generation code (3DFAM) has been developed to model the fracture network based on the mapped data. The code has been validated on the basis of numerous geometrical characteristics computed by use of the linear, areal sampling methods and volumetric method. Results of the linear sampling method have significant variations. So, the areal and volumetric methods are more efficient than the linear method and they are more appropriate for validation of 3D DFN (Discrete Fracture Network) codes.

Kinetic, isotherm and thermodynamic study of nitrate adsorption from aqueous solution using modified rice husk

Reza Katal,Hooman Taher Rahmati,Hossein Esfandian,Mazyar Sharifzadeh Baei 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.1

In this article, we prepared anionic sorbent using rice husk (RC). Anionic rice husk (ARC) structural characteristics and adsorption properties for nitrate removal from aqueous solution were investigated. The sorption of NO3by batch method is carried out. The optimum conditions of sorption were found to be: a sorbent dose of 0.4 g in 100 mL of NO3solution, contact time of 90 min, pH = 7. In optimum condition, removal efficiency was 94.3% for the NO3. The nitrate adsorption process was well described by the pseudo-second-order kinetic model, and the experimental isotherm data fitted well with the Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. Thermodynamic parameters such as Gibbs free energy change, enthalpy change and entropy change were calculated and the results showed that the adsorption of nitrate on ARC was spontaneous and exothermic in nature. The effect of other anions were also studied and was found that the anions reduced the nitrate adsorption in the order of carbonate > chloride > phosphate > sulphate. ARC was used for the removal of NO3from real wastewater (urban wastewater) that high performance of adsorbent was considerable.