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Showing 11 results for Mehrasbi

Mohammad Reza Mehrasbi, Ghasem Mohammadi, Mehran Mohammadian Fazli, Bahram Hajikarim, Gholamali Jafari,
Volume 1, Issue 1 (12-2015)
Abstract

Background: Bio aerosols include airborne micro-organisms such as bacteria, fungi, viruses, etc and their products. Exposure to a bio aerosol is linked with a broad spectrum of health problems, including infectious diseases, acute toxic effects, allergies, and cancer. The aim of this study was to evaluate the quality and quantity of bio aerosols found in the air of different wards in Valiasr Hospital, Zanjan, in summer and fall 2012.
Methods: Air samples were collected from six wards including: operating room, infectious, ear, nose, and throat (ENT), surgery, adult intensive care unit (ICU), oncology and administrative with a single-step Anderson sampler. The type and number of colonies were determined in the laboratory, and then the bio aerosol density were calculated in terms of cfu/m3 and compared with the recommended limits.
Results: The most common genera of isolated bacteria and fungi were Staphylococcus and Penicillium, respectively. In the infectious ward bacterial density was higher than the recommended limit of WHO (100cfu/m3) in the visiting times (afternoon). The fungal density in the meeting time (afternoon) in the ICU, ENT, and general surgery, infectious and administrative wards, and in non-visiting times (morning) in the infectious ward was higher than the recommended limit of WHO (50 cfu/m3).
Conclusion: From the findings of this study it can be concluded that the density of fungi and bacteria in the hospital air in some times of working period are higher than recommended levels and therefore, the condition of existing air filtration and ventilation systems should be appropriated according to the international standards of hospitals buildings.


Mohammad Reza Mehrasbi, Zohre Farahmand Kia,
Volume 1, Issue 1 (12-2015)
Abstract

Background: Qual2k is a stream water quality model and was used to evaluate the water quality of the Kine-Vars River and assess the response of the river to nutrient management strategies.
Methods: For that purpose, 7 sample stations were selected and surface water samples were collected in the winter and summer of 2012 and were analyzed for temperature, dissolved oxygen, biological oxygen demand, ammonia–nitrogen, nitrate–nitrogen, organic nitrogen, organic phosphorus, and inorganic phosphorus.

Results: Results showed that the Kine-Vars River is saturated with N and P and is classified as eutrophic. The simulated data showed that the total nitrogen and total phosphorus loads of the studied river need to be reduced by 76% and 93%, respectively, to reach water quality objectives.
Conclusion: Application of nutrient control strategies can reduce the nutrient loads significantly but is not sufficient to change the river classification from eutrophic to oligotrophic in a short time; thus, additional nutrient control measures are necessary.


Negin Soleimani, Mehran Mohammadian Fazli, Ali Ramazani, Mohammad Reza Mehrasbi,
Volume 1, Issue 2 (3-2016)
Abstract

Background: Various industries produce and discharge wastes containing different heavy metals into the environment. Apart from using living biomass, dead and dried biomasses have been introduced as a new field of biotreatment technology.
Method: The cadmium (Cd) (II) removal characteristics of live (growing), dead (autoclaved), and oven-dried biomasses of Aspergillus versicolor were examined as a function of initial pH, contact time, and initial Cd concentration.
Result: Maximum bioaccumulation of Cd for live biomass [11.63 (mg g¹)] occurred at an optimal pH of 4 and incubation time of 4 days. Themaximum biosorption of 27.56 (mg g¹) for dead biomass occurred at 1.5 h and at a pH of 4. The maximum biosorption [18.08 (mg g¹)] with dried biomass was reached at an equilibrium time of 3 h at a pH of 6.
Conclusion: The present study confirmed that heat treatment promoted the removal capacity of fungi. Cd removal was increased by decreasing the pH in live and dead-mode experiments. Inversely, Cd removal was increased with increasing pH for the dried biomass of A. versicolor. Varying responses to environmental conditions (pH and contact time) clearly proved the different removal mechanisms used by three biomasses of A. versicolor. Higher Cd concentration increased the removal ability of three types of biomasses. The results indicated that all biomasses of A. versicolor used in this study, particularly dead biomass, are a suitable biosorbent for the removal of Cd (II) ions from aqueous solution.

 


Mohammad Reza Mehrasbi, Rohangiz Moradjoo, Mehran Mohseni, Koroosh Kamali, Zohre Farahmankia, Jafar Taran,
Volume 1, Issue 2 (3-2016)
Abstract

Background: Dithiocarbamates, the main group of fungicides, are used to control about 400 pathogens in more than 70 crops. These pesticides are widely applied to crops including potato, cereal, apple, pear and leafy vegetables throughout the world since 1960. From the late 1980s, using these fungicides has caused much debate among regulators about their long-term effects on consumers and occupational users.
Method:  In this study the residues of Dithiocarbamates in cucumber and tomato using the colorimetric method (Keppel method) was measured. Respectively 80 and 45 samples of greenhouse cucumber and tomato were collected from Zanjan vegetables center in autumns and winter 2013. The samples were analyzed in 4 treatments of: unwashed, washing with water, washing whit detergent and peeling.
Result: The results showed that the average concentration of Dithiocarbamates residues in unwashed greenhouse cucumber and tomatoes were 384.5 µg/kg and 65 µg/kg respectively. 35% and 5% of unwashed and water washed cucumber and tomato   samples (respectively) had higher Dithiocarbamates residue than MRL recommended by Institute of Standards and Industrial Research of Iran (0.5mg/kg).
Conclusion: The treatments of washing and peeling had significant effect on the reduction of Dithiocarbamates residues in the all samples.


Mohammad Reze Mehrasbi, Faranak Saghatchi, Zahra Khodaei, Jose Luis Gutierrez-Villanueva, Koroosh Kamali,
Volume 1, Issue 3 (6-2016)
Abstract

Background: Environmental gamma ray refers to the gamma radiation from terrestrial sources and building materials. In enclosed spaces radiation can become a health hazard leading to potential increase in the rates of lung cancer. The goal of this study is to assess the exposure to natural gamma radiation of children in the schools of Zanjan province.
Method:The natural gamma radiation was assessed in 46 primary schools of Zanjan province. A total number of 75 classrooms were studied. The measurements were performed in classrooms and schoolyards using a Geiger–Muller detector (RDS-110). Alongside radiation measurements, all the data corresponding to the characteristics of each school building were collected.

Results: The results showed that the outdoor dose rate ranged from 82 to 106nSv h-1 while gamma dose rate due to inside classrooms ranged from 106 to 137nSvh-1. The findings represented that the highest indoor gamma dose rate belonged to the buildings of more than 30 years and metal frame and brick (P<0.05).

Conclusion: We concluded that the effective dose due to gamma radiation from terrestrial sources and building materials for students of primary schools in Zanjan province (0.83 mSv) was higher than worldwide average of the annual effective dose (0.48 mSv).


Mazyar Peyda, Mohammad Reza Mehrasbi, Masoud Naderi, Koorosh Kamali, Vahid Fallah Abadi,
Volume 1, Issue 4 (9-2016)
Abstract

Background; Contamination of water and soil through non-point sources such as road runoff causes environmental concern. The aim of this study is to determine the effect of Zanjan – Chavarzagh road on the total organic carbon (TOC) content of sediments in tributaries and the river that lead to Taham Lake.
Methods; In tributaries and the river 69 soil and sediment samples were taken and the Total organic carbon (TOC) was measured according to Walkely-Black method. Also, Taham Dam Basin area and its hydrologic properties were calculated by Global Information System (GIS) software.
Results; Results showed that, TOC concentration has a significant negative relationship with the distance from the lake. TOC in soil samples taken from hillside of the road had significantly lower mean and median concentration ( median= 3262 , mean = 4083 ± 3461  mg/kg) than the valley side ( median = 5324 , mean = 6178 ± 3980  mg/kg). The check dams across the tributaries and the river have not been effective in the reduction of TOC in sediments.
Conclusion; Roads in the Taham Dam Basin, increases TOC content of soil and sediments in Taham dam basin. TOC moves toward Taham dam lake.


Javad Mohammadi, Mehdi Mohammadi, Mohammad Reza Mehrasbi, Mazyar Peyda,
Volume 1, Issue 4 (9-2016)
Abstract

Background; Enzymes are well known as sensitive catalysts in the laboratory and industrial scale. To improve their properties and for using their significant potential in various reactions as a useful catalyst the stability of enzymes can often require improvement. Enzymes Immobilization on solid supports such as epoxy- functionalized ferric silica nanocomposite can be effective way to improve their characteristics.
Methods; In this study silica coated magnetite nanoparticles were Functionalized with GPTSM as a linker, then immobilization reaction performed by using  various amounts of lipase B from Candida Antarctica (CALB), for the next step immobilization effects on thermal stability and optimum pH were investigated in comparison with free CALB.

Results; Results illustrated enzyme was successfully immobilized on nano particles and immobilized derivative retains 100% of its activity by 55°C while free CALB loss its activity at the same condition.
Conclusion; Immobilization of CALB on Fe3O4@SiO2 particles resulted in significant improvements in its characteristics such as thermal stability and methanol tolerance compared to the free CALB.


Khalilollah Moeinian, Mohammad Reza Mehrasbi, Hassan Hassanzadazar, Koorosh Kamali, Elaheh Rabiei ,
Volume 2, Issue 1 (12-2016)
Abstract

Background; Fluoride is an essential nutrient for the human body. The major routes of fluoride intake include food and drinking water, though the absorption of fluoride from food is much easier. The aim of this study was to evaluate the amount of fluoride in the soil and tomato and onion crops on farms of Zanjan.

Methods; Three farms of each crop (tomato and onion) were selected randomly. Each farm was divided into 10 sections, and one sample of soil and crop of each section was taken which means 120 samples in total. Fluoride concentrations in the soil and crops were measured using the Ion Selective Electrode (ISE) and repeated 3 times.

Results; The mean concentration of fluoride in soil samples from studied farms in Zanjan was 0.83 ± 0.17 mg/kg. The mean concentrations of fluoride in tomatoes and onions of Zanjan were observed 2.10 ± 0.80 and 2.23 ± 0.64 mg/kg, respectively.

Conclusion;There was no significant difference between fluoride concentration in tomatoes and onions, although there was a significant difference between the amount of fluoride in the soils of studied farms (Pv < 0.024). No significant correlation was observed between the fluoride levels of soils and the fluoride levels of tomatoes (R2 = 0.126) and onions (R2 = 0.008).


Zahra Abedi, Mohammad Reza Mehrasbi, Ali Assadi,
Volume 2, Issue 4 (9-2017)
Abstract

Background: Natural organic matters (NOMs) have the main role in formation of trihalomethanes. These compounds are in natural water sources due to biological activities. In the presented study, adsorption and separation of humic acid as an index of natural organic matters using multi-walled carbon nanotubes is evaluated.
Methods: The experiments were carried out in bath adsorption reactors with different concentrations of humic acid. The effects of pH, adsorbent dose, national concentrations of humic acid and contact time as study variables were tested in separated experiments, as well as, kinetic and isotherm models of the adsorption process were determined.
Results: The results showed that the adsorption follows Freundlich isotherm model and pseudo second-order kinetic equation. The removal percent of humic acid reached to higher than 90% with dosage of 1g/l of nanotube.
Conclusion: Adsorption of humic acid from water by multi-walled carbon nanotubes is an efficient alternative pretreatment method in water treatment plants.

 
Ali Assadi, Tohid Soltani, Mohammad Reza Mehrasbi,
Volume 3, Issue 1 (12-2017)
Abstract

 Nowadays, underground water is the main source of drinking water that contamination to organic pollutants such as MTBE is an important issue. One of the suitable methods for these types of pollutants is the advanced oxidation methods. Advanced oxidation processes (AOPs) are involved in the production of highly reactive hydroxyl radicals that oxidize organic matter such as MTBE and even lead to its full mineralization. The use of light in the presence of catalysts is one of the methods of advanced oxidation processes. Photocatalytic methods widely used for a wide range of toxic and none degradable pollutants. Recent advances in the fabrication and characterization of Nano scale materials have extensively developed research into methods for the preparation of highly effective Nano-sized catalysts for the removal of chemical contaminants. This review article discusses the work on the photo catalysis of MTBE in water using different types of photo catalysts.


Mohammad Reza Mehrasbi,
Volume 4, Issue 2 (6-2018)
Abstract


This article has no abstract
 

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