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Showing 13 results for basiri


Volume 11, Issue 0 (بهار و تابستان 87- 2008)
Abstract

Objective: Helicobacter pylori is a spiral, microaerophilic gram negative bacterium, that multiplies and causes infection in human gastric mucosal layer. H.pylori infection, followed by destruction of gastric epithelial tissue, leads to gastric chronic inflammation, which can cause gastric and peptic ulcers. New approaches have focused on using specific treatments, such as immunotherapy, to eradicate this infection. Urease, as one of the most important virulent and antigenic factors of the bacterium, is a suitable target for this purpose. This study is aimed at production of specific IgY against urease UreC subunit. Materials and Methods: In this study, initially for preparing recombinant UreC, after purification of the genomic DNA, ureC gene was amplified by polymerase chain reaction (PCR). The PCR product was ligated to pET28a. The recombinant protein was expressed followed by transformation of recombinant construct into E. coli BL21DE3. SDS-PAGE analysis was carried out and the recombinant protein was purified by Ni-NTA affinity chromatography. The purified recombinant protein was injected to hens. IgY recovered from egg yolk, was purified by PEG precipitation at >70% purity. The purified IgY was analyzed by ELISA and SDS-PAGE. Results: SDS-PAGE analysis revealed a good expression and >70% purification of the recombinant protein. ELISA observation demonstrated high immunogenicity of the recombinant protein. Conclusion: With a view to higher potential of IgY-HpUc in recognition of UreC subunit, the results are in favour of the oral administration of the IgY obtained from hens immunized by H.pylori may provide a novel approach to the management of H.pylori infections.

Volume 13, Issue 3 (July & August 2022 (Articles in English & French) 2022)
Abstract

Early-career language teachers, who are struggling with transitory stages of identity development from students to teachers, can experience an array of negative emotions known as identity tensions. Coping strategies are used by resilient teachers to overcome these tensions. However, the nature and dynamics of such coping strategies employed by EFL teachers are still under-researched in the Iranian context. In order to address this gap, the present exploratory mixed-methods study probed the coping strategies Iranian EFL teachers most frequently use by first interviewing 16 teachers and, subsequently, administrating a developed questionnaire to a cohort of 150 participants. Thematic analysis and between-groups analyses of t-tests and ANOVAs were used for the qualitative and quantitative phases of the study respectively. The results of both phases revealed that Iranian EFL teachers tend to use active coping strategies significantly more often than passive ones. Also, it was shown that female teachers as well as more experienced teachers above the average age of 28 use more active strategies than their younger colleagues. However, type of training did not seem to play a significant role in their choices, which implies a need for a more systematic integration of coping strategy instruction in training programs. The findings of this study can help English teacher trainers, supervisors, and novice teachers form a deeper insight of coping strategies to deal with identity tensions.    
 

Volume 13, Issue 14 (Second Special Issue 2014)
Abstract

Carbon nanotubes (CNTs) are rolled form of graphene sheet with unique properties due to the covalent bonds between carbon atoms. In this research, different structures of CNTs are studied for a wide range of diameter and length to determine the influence of chiral angle on their shear and bending modulus. Covalent bands between carbon atoms are simulated using linear beam elements based on molecular mechanics and finite element method. By using finite element analysis, the effects of diameter, length and chiral angel of nanotubes on mechanical properties under torsional and bending loading conditions are studied. The results show that zigzag CNT has the least shear and bending modulus comparing the armchair and chiral structures. Chiral nanotubes with angles smaller than 17 degrees has less shear modulus comparing armchair ones. But, for larger angles, chiral nanotubes has the largest shear modulus. Also, bending modulus of chiral CNTs is larger than armchair and zigzag structures.

Volume 15, Issue 11 (1-2016)
Abstract

Abstract- In this study, effect of adding graphene and poly olefin elastomer (POE) in polypropylene matrix, in various mix time were studied. Method of fabrication samples were melt-blending samples with 0, 2, and 4 %wt of graphene, 0, 15, and 30 %wt of POE and 8,12, and 16 minute mixing time were used. For a better analysis of mechanical properties, tensile and impact tests and DSC, SEM analyses were employed. Results of tensile tests indicated that adding of POE caused reduction of elastic modulus, reduction of tensile strength, good improvement of impact strength and poor improvement of elongation. While presence of graphene caused a good improvement of modulus, without meaningful effect on tensile strength, reduction of elongation and poor improvement of impact strength. DSC analysis of samples showed that graphene and POE has no visible effect on degree of crystallinity but graphen cause temperature of crystallinity increased. SEM observations showed that byincreasing of mixing time an improvehappens on dispersion of grapheme.A reduction in size of POE particles in blending of course agglomerations of grapheme in all samples were showed that for the method of fabrication , surface area of graphene and percents of graphene in samples was not unexpected.

Volume 16, Issue 89 (7-2019)
Abstract

The berry tree is native to the dry climates such as Iran. Its fruit is juicy and rich in sugars, minerals and vitamins. Condensed mulberry extract has a lot of applications in various food industries as sweetener. The purpose of this study was to introduce a suitable method for production of high quality mulberry extract in order to prevent the loss of mulberries at the time of production peak and use the unique properties of berry fruit outside of the production season. In this project, three concentrating methods such as sunny, under conventional conditions and vacuum concentration were used to produce samples with desired brix of 65. Samples were packed in plastic pet bottles and kept in a lab environment away from sunlight for 3 months. Physicochemical experiments including pH, acidity, consistency, color, transparency and sensory properties such as flavor, aroma, concentration and total acceptance of samples were performed in two stages of 3 months and the results compared with each other. The results showed that the color factors L a b were more suitable in traditional samples. These factors decreased over time. The highest pH belonged to the industrial sample (4.84) and the lowest pH belonged to the sunny sample (4.61), and the pH of the samples decreased over time. The transparency of sunny sample (1.57) and industrial (0.804) were the highest and the lowest, respectively and transparency increased over time. In terms of sensory properties, the taste and aroma of traditional sample with scores (3) and (2.916) and the concentration of sunny sample with score (3.416) were the best samples. In conclusion, the traditional sample was selected, and the sunny sample was ranked second.


Volume 16, Issue 92 (october 2019)
Abstract

Honey is a natural sweet substance that the bee collects, treats it from the floral nectar and stores it in honeycombs. Honey has many nutritional and medicinal properties. The purpose of this research is to determine the effect of honey production area and its harvest time on the physicochemical and antioxidant properties of natural honey. Honey samples were collected from three areas of Shirvan, Kashmar and Neyshabour in Khorasan Province in two different seasons, spring and autumn. The honey was completely pure and was made from natural flowers in the region. In this research, some physicochemical, antioxidant and microbial properties of honey samples were evaluated. The results showed that spring honey samples with a moisture content (16.6%) and brix (81.36%) had the highest and lowest moisture content and Brix degree respectively than the samples harvested in the fall. Also, spring honey with a color intensity of 0.005%, had a brighter color than the autumn samples. Also, spring honey had more phenolic compounds (0.067 mg/kg honey) and higher antioxidant and antibacterial properties (respectively 61.1856, 100%) than the fall samples. Among honey samples, Kashmar honey had the highest antioxidant capacity (54.3) and honey Neishabour had the highest amount of phenolic compounds (0.052 mg/kg). Antimicrobial effect of Shirvan honey samples was the highest (83.33%). All honey samples did not contain sulfite reducing bacteria that indicated correct hygienic management in honey processing and showed good microbial quality of honey samples. All of the honey samples did not contain sulfite reducing bacteria, which show proper hygienic management in honey processing and appropriate microbial quality of honey samples.

Volume 17, Issue 98 (April 2020)
Abstract

Button mushroom has sensible to mechanical blows and has low shelf life. The purpose of this project was determining of the optimum method of ultrasonic dehydration and the effect of osmotic processing conditions on mass transfers. In the first step, sodium chloride solution with concentrations 6, 9, 12 and 15%, for 20,40,60,90 and 120 minutes at 25°C and 45°C were used and in the second step, in the constant conditions of salt concentration (12%), immersion time (60 min) and temperature (45°C), the mushroom samples were subjected to ultrasonic wave in two levels (pulse duration time to pulse rest time of 1:1 and 1:4) at frequency of 20 KHz and constant power 400 w, to determine their effect on water loss, solid gain and water reduction. The results showed that, as the concentration of osmotic solution increased, mass transfer from the sample increased. When immersion time was increased to 60 min, solid gain and moisture diffusion increased. After this time, water loss was less increased and solid gain was more increased. Further solid gain created a resistant layer against permeability and solute movements on both sides of tissue. in this process, at temperature of 45 °C, greater the mass transfer rate achieved, mainly due to the increase in cell permeability and permeability coefficient. It was found that salt concentration of 12%, immersion time of 60 min and temperature of 45°C gave the minimum solid gain (2.83%) and maximum water loss (29.36%) and weight reduction (24.53%). Also, the use of ultrasound with pulse ratio of 1:1 in constant osmotic dehydration condition was conducted better results. At 40 min processing time, the solid gain, water loss and weight reduction were 2.93%, 41.23% and 40.30%, respectively.Moisture content of mushrooms after osmotic dehydration and ultrasound treatment reduced to 85 and 82 %, respectively.
 

Volume 17, Issue 105 (November 2020)
Abstract

Food fortification for the prevention and treatment of micronutrient deficiency disorders is one of the most widely methods that because of its low cost and no need to change dietary habits was used all around the world. In grain fortification, immersion and spraying methods are usually used, and extrusion processes are used for cereal flour. In extrusion fortification method, the used extensions are into the food matrix so their output during different processing stages is less than other enrichment methods. In this study, rice reconstituted by extrusion cooking method, was enriched with vitamin D3 (100000 IU/g) at concentrations of 2.5, 5, 7.5 and 10 µg/100g and Zinc (as Zinc oxide) concentrations of 5, 10, 15 and 20 mg/100g and then remaining of Vitamin D3 and Zinc were measured before and after extrusion and before and after cooking in 30 days intervals during 180 days storage period. According to the results, storage period and also the cooking process at all initial concentrations have a significant effect (p<0.5) on Vitamin D3 and Zinc stability of extruded fortified rice so that the average content of Vitamin D3 and Zinc at the end of storage period of 180 days showed a loss of 32.9 and 11.3% (before cooking), 38.9 and 24.0% (after cooking), respectively but these materials had a good stability during the extrusion process. Overall, during the different processing stages, the average content of Vitamin D3 and Zinc showed a loss of 87.1 and 39.0%, respectively.
 

Volume 18, Issue 121 (March 2022)
Abstract

With increasing public awareness, the demand for healthy foods has increased. Low resistance of probiotic bacteria against adverse environmental conditions is one of the most important factors limiting the production and development of probiotic products. Encapsulation by enclosing probiotic cells can increase stability against limiting factors such as gastric acidity. In this study, the efficiency of double layer encapsulation with sodium alginate and chitosan by spray drying and emulsion methods on the stability of Lactobacillus acidophilus under simulated gastric conditions (pH=2) during 0, 30, 60, 90 and 120 minutes were examined. The size of the microcapsules was determined by the particle size analyzer and their morphology using a scanning electron microscope (SEM). The obtained growth curve showed that the bacteria enter a stationary growth phase 40 to 42 hours after inoculation. The size of the microcapsules obtained from the emulsion method were significantly (p≤ 0.05) smaller than the spray drying method. The morphology of the microcapsules was spherical to oval, and the samples obtained from the spray drying method had a shrinked surface. The highest survival was shown by emulsion encapsulated samples with a decrease of 1.9 logarithmic cycles, followed by spray dried encapsulated bacteria with a reduction of 2.4 logarithmic cycles. The lowest survival rate was related to the control sample (free bacteria) with a decrease of 3.83 logarithmic cycles. Encapsulation of Lactobacillus acidophilus probiotic bacteria by the emulsion technique by creating appropriate stability under simulated gastric conditions is a suitable method to obtain probiotic products enriched with this bacterium.

Volume 19, Issue 6 (12-2019)
Abstract

With increasing urban population, the need for underground spaces increases and deep excavation is an inevitable affair in civil projects. deep tunnels and large buildings require deep excavations, which is a must use some techniques for stabilize it. grouted soil nail is a popular reinforcement to stabilize slopes, excavations and retaining walls. This method has been introduced to Hong Kong in the mid-1980s and has become an alternative solution to the conventional slope stabilizing methods such as compaction, earth retaining structure, or reduced inclination of the slope, etc. this method is based on sewing the potential failure wedge of soil on the stable soil using some inactive (un-prestressed) elements. the shear strength-displacement behavior at the interface between the grouted nail and surrounding soil is an important parameter in design of various geotechnical engineering projects, for example, soil nails, retaining walls, shallow foundations, pile foundations, etc. in soil nail system, the most common method to measure the interface shear strength is pullout test. It is also possible to determine the interface strength based on the development of resistance between soil and grout in direct shear tests. However, accurate perception of the shear behavior in the connection area of the soil and grout is essential to reach an optimum design. In other words, the interaction between soil and grouted nail is necessary to design an optimum soil nail system. the most common method for determination grouted soil interface resistance is pullout test but there is another experiment that can yield acceptable results. The current study investigates the interface shear behavior between cement-grout and granular soil in direct shear test with different grout pressures ( up to bar) and different overburden pressures ( up to 300 kPa). For this purpose, a number of direct shear tests are performed by modifying of the standard shear box for injection of grout. “Firozkooh” sand is used in this study. The soil is compacted to the relative density of % and the slurry is sprayed with pressure on its surface. Furthermore, results of two pullout tests were used for verification. These pullout test have already been presented in another study with different normal stress and grout pressure. it is shown that the results of direct shear test and pullout test at interface are similar. this may indicate the proper function of direct shear test as a suitable choice alongside pullout test. It was observed that shear stress–displacement curves of the soil-grout interface in direct shear tests are similar to the soil-soil tests; which are classified under different grouting pressures. In addition, increasing grout pressure increases shear strength by increasing the angle of friction and bonding of soil and slurry. The effect of adhesion is dominant. it is shown that The interface shear stress under different grouting pressures is greater than the shear stress of soil under the same normal stresses. it is shown that grouting pressure and normal stress have influence on the behavior of soil-cement interface. Therefore, interface shear strength increases with increase in overburden and injection pressure. The variation of the interface shear strength is approximately linear versus grouting pressure. Finally, a formula is proposed for interface shear strength considering grouting pressure.

Volume 19, Issue 123 (May 2022)
Abstract

In this study, using thyme medicinal plant without using heat by osmotic method, sugar solution with maximum active ingredients was produced. Effects of temperature (25, 35 and 45 degrees Celsius), sucrose osmotic solution concentration (40, 50 and 60%) and sampling time (15, 30, 60, 90, 120, 180, 240 and 360 minutes) on the amount The removal of active ingredients from the plant and the change in pH values and electrical conductivity (EC) were evaluated. Then the effect of blanching with hot water in (30, 60, 120 and 180 seconds) and ultrasound (0, 15 and 30 minutes) on the osmotic processing were investigated separately. The highest EC was in the solution with 40% sucrose concentration and 45°C and the lowest was in osmotic solution with 60% concentration and 45°C. Blanching before osmosis resulted in increased pH and EC. Blanching for 30 seconds caused the greatest increase in EC. Treatment with 30 minutes ultrasound increased the pH and EC in samples compared to 15 minutes of ultrasound. The chromatographic results of the control samples and the sample containing thyme extract in sucrose solution showed the release of polar and non-polar active compounds in the osmotic solution. The release of different compounds showed a difference in their release rate during the osmosis process. Finally the results showed that the extraction of active ingredients of medicinal plants was possible by osmosis process, so that the pH and EC changed over time. The product of this research can be used in the production of beverage syrups and food. In this method, the damages of other methods of extraction of effective substances such as solvent extraction, use of heat in extraction and drying of medicinal plants such as distillation and essential oil extraction methods are minimized.

Volume 19, Issue 124 (June 2022)
Abstract

Tomatoes are widely produced and consumed worldwide due to their high nutritional value as well as unique sensory properties. The high perishability and low shelf life of tomatoes necessitate the use of modern processing methods. In this research, the possibility of using vacuum frying technology in the processing of tomato slices, the effect of process variables (processing time, oil temperature and pressure inside the chamber) on some quality characteristics of the final product (moisture and fat content, Shrinkage, ascorbic acid, color and texture brittleness) as well as determining the optimal processing conditions in a vacuum lab-scale frying system with precise control of process conditions were investigated. Initially, by performing pre-tests, the range of variables of the study included frying temperature, pressure inside the chamber and process time was determined. The results of study showed that the process temperature has significant effects on the moisture content, shrinkage, fat content, ascorbic acid content and texture brittleness, so that with increasing temperature, the content Moisture and ascorbic acid content decrease and shrinkage, fat content and tissue brittleness increase. Processing time showed significant effects on the moisture content, shrinkage, fat content and texture brittleness, so that with increasing process time, the moisture content decreased and shrinkage, the fat content and texture brittleness, increased. Pressure of the study area had significant effects only on shrinkage and total color change characteristics. Increasing the pressure inside the chamber led to a reduction in shrinkage and an increase in total color changes. Optimum vacuum frying conditions of tomato slices were a temperature of 135°C, time of 21.92 minutes and pressure of 260 mbar, under these conditions were the moisture content, shrinkage, fat content, amount of ascorbic acid, total color changes and the breaking force were 45.93%, 70.54%, 34.64%, 2.92 mg/100 mL, 64.86 and 2.58N, respectively.

Volume 25, Issue 6 (11-2023)
Abstract

Jujube is one of the most important horticultural fruits with high nutritional and medicinal value. Due to the short shelf life of fresh jujube, consumption of fresh fruit is low. This study aimed to evaluate the treatments affecting the quality of three fresh jujube cultivars. Treatments included jujube cultivars (commercial, Mazhan, and Siojan), fruit harvest time (semi-mature and fully mature), foliar spraying of trees (0 and 2%), and storage time (20 and 35 days). Assessed traits were brix, acidity, firmness, Ascorbic acid, total phenolic compounds, and color indexes (L ⃰ a ⃰ b ⃰). Calcium chloride solution was used to improve the quality and shelf life of fruits. Jujube fruits were stored in a refrigerator at 5°C. Data analysis was performed using a factorial experiment based on a completely randomized design and three replications. Results showed the Siojan cultivar had the best quality characteristics: its phenol content was 2.438 mg gallic acid/gr solid weight, the ascorbic acid value was 929.91 mg 100 g-1, the firmness was 7,390 N m-1, and its Lightness (L ⃰) was 27.71. Foliar spraying treatment was approved for the firmness and color of fruits. After 20 days, firmness (10,460 N m-1) and ascorbic acid (924.843 mg 100 g-1) were maintained, and after 35 days, total phenol (2.447 mg gallic acid g-1 solid weight) was increased. The sensory analyses results showed Siojan cultivar with other advantages, including large size, good taste, and high flesh to kernel ratio. Overall, Siojan cultivar had a good shelf life of up to 20 days at 5°C.

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