49 research outputs found
A Predictive Model for the Strength of a Novel Geopolymer Construction Material Produced by Autoclaved Aerated Concrete Waste
Carbon dioxide emission and consumption of large amounts of natural resources are the environmental hazards observed in the production process of various commonly used construction materials, like Portland cement and clay bricks. Also, debris from the demolition of old buildings and disposing of the waste of construction material factories also cause environmental pollution. Producing environmentally friendly geopolymer materials with recycling construction wastes containing aluminosilicate resources and alkaline activators could be an effective method for reduction of environmental hazards. This paper is an innovative feasibility study of geopolymer material production using the waste autoclaved aerated concrete (AAC) powder. Here, a mix of AAC powder together with activator solution containing sodium hydroxide and sodium silicate at different concentrations was used to prepare the geopolymer mortar samples. The specimens were oven-cured at different temperatures. The effects of sodium hydroxide concentration and curing temperature on the compressive, tensile, and flexural strengths, as well as water absorption of the samples, were investigated. The main contribution of this study is the feasibility of the successful fabrication of geopolymer material based on AAC waste powder with desirable mechanical properties. Namely, the compressive strength of the base AAC blocks used here was 3 MPa and the maximum strength of the produced geopolymer material using the AAC powder was about 21 MPa. The test results were used to develop a model to predict the compressive strength of the proposed geopolymer AAC material to the effective parameters by Gene Expression Programming. The model predictions were confirmed using an extra series of test results implemented by the authors
Amino acids status in Iranian rice (Oryza sativa L.) as affected by different salt compositions
Salinity is one of the major problems to increasing rice production in paddy field. The role of free amino acids as compatible solutes is controversial and the different salt compositions effect on rice response to salinity stress is not completely clear. Therefore a glasshouse experiment was carried out to determine free amino acid/acids which are involve in defense mechanism under salt stress conditions and different salt compositions effects on free amino acids status at seedling stage. Two rice genotypes differing in salinity resistance were grown hydroponically. The rice seedlings were exposed to salinity stress at EC 7 dS.m-1 by NaCl and mixture of NaCl:Na2SO4 at 1:2 and 2:1 molar ratios. Free amino acids in shoot and root tissue of rice seedlings were measured using high performance liquid chromatography (HPLC). The rice seedlings significantly showed amino acids accumulation in their shoots greater than in their roots. Khazar, a salt sensitive genotype, demonstrated higher total free amino acids and aspargine than Fajr, a salt tolerant genotype. A positive correlation between aspargine accumulation and water content percentage in shoot tissue was recorded. Likewise the results revealed that there was a significant difference across salt compositions. It was suggested that SO42 decreased Cl toxicity effects on rice seedlings growth
Seed germination and proline accumulation in rice (oryza sativa L.) as affected by salt concentrations
Plant cells accumulate praline as an osmoprotectant to conserve osmotic stability and prevent damage. However,
the accumulation of proline may not be associated with tolerance to salinity. This study considered the influences
of NaCl and Na2SO4 compositions, at different concentrations, on seed germination and accumulation of proline in eleven rice genotypes. Rice seeds were grown in petri dishes in the laboratory and treated with distilled
water as a control and NaCl and Na2SO4 (1:1 molar concentration ratio) at 2.5, 5.0, 7.5 and 10 dS m-1 electrical
conductivity for 14 days. The mean germination time (MGT) was positively affected by the increase in the
concentration of salt. Conversely, there was a negative relationship between germination index (GI) and salt
concentration. Shirodi, Fajr, and Shafag can be classified into salt tolerant group, while Tarom-e-Hashemi
was identified as salt susceptible, based on MGT and GI. Slight changes were recorded within dry weight
and water content of seedlings at different salt levels. The maximum accumulation of proline was observed
at 5 dS m-1 salt concentration. No relationship was established between the accumulation of proline and the
growth parameters
A Feasibility Study on Using the Facilities of Health Centers for Developing a Laboratory Network on Vectors and Reservoir Hosts of Cutaneous Leishmaniasis in Iran
Background: Cutaneous leishmaniasis is an ancient endemic disease in Iran and continues to be a growing health threat to community development and the environment. This paper explains how to use the facilities of health centers for developing a laboratory network on vectors and reservoir hosts of cutaneous leishmaniasis in Iran. Methods: A literature search was performed of the relevant multiple databases to include studies on vectors and reservoirs of cutaneous leishmaniasis in Iran. A team of experienced experts was performed. After holding several meetings, field visits and organizing workshops, the activities of laboratories were determined at three levels. Results: Entomological studies showed that 5 species of the genus Phlebotomus and 10 species of the genus Sergentomyia are active in the south, 4 species of the genus Phlebotomus and one species of the genus Sergentomyia in the central part and 5 species of the genus Phlebotomus and 2 species of the genus Sergentomyia in the north east. Reservoir hosts were identified in the study areas. The tasks of laboratories were regulated at different levels. Conclusion: The Iranian Ministry of Health and Medical Education should prioritize the employment of capable persons in the field of Medical Entomology and Vector Control. The survival of this laboratory network depends on hiring and employing interested and persistent people. The universities of Medical Sciences that have the facilities to set up this network will be a very effective partner in the control of the disease in high risk areas. The results can be used in neighboring countries.Fil: Reza Yaghoobi Ershadi, Mohammad. Tehran University of Medical Sciences; IránFil: Akhavan, Amir Ahmad. Tehran University of Medical Sciences; IránFil: Reza Shirzadi, Mohammad. Iranian Ministry of Health and Medical Education; IránFil: Zohreh Hosseini, Seyedeh. Tehran University of Medical Sciences; IránFil: Salomón, Oscar Daniel. Secretaria de Gobierno de Salud. Instituto Nacional de Medicina Tropical. Instituto Nacional de Medicina Tropical - Sede Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Hanafi Bojd, Ahmad Ali. Tehran University of Medical Sciences; IránFil: Rassi, Yavar. Tehran University of Medical Sciences; Irá
A Feasibility Study on Using the Facilities of Health Centers for Developing a Laboratory Network on Vectors and Reservoir Hosts of Cutaneous Leishmaniasis in Iran
Background: Cutaneous leishmaniasis is an ancient endemic disease in Iran and continues to be a growing health threat to community development and the environment. This paper explains how to use the facilities of health centers for developing a laboratory network on vectors and reservoir hosts of cutaneous leishmaniasis in Iran. Methods: A literature search was performed of the relevant multiple databases to include studies on vectors and reservoirs of cutaneous leishmaniasis in Iran. A team of experienced experts was performed. After holding several meetings, field visits and organizing workshops, the activities of laboratories were determined at three levels. Results: Entomological studies showed that 5 species of the genus Phlebotomus and 10 species of the genus Sergentomyia are active in the south, 4 species of the genus Phlebotomus and one species of the genus Sergentomyia in the central part and 5 species of the genus Phlebotomus and 2 species of the genus Sergentomyia in the north east. Reservoir hosts were identified in the study areas. The tasks of laboratories were regulated at different levels. Conclusion: The Iranian Ministry of Health and Medical Education should prioritize the employment of capable persons in the field of Medical Entomology and Vector Control. The survival of this laboratory network depends on hiring and employing interested and persistent people. The universities of Medical Sciences that have the facilities to set up this network will be a very effective partner in the control of the disease in high risk areas. The results can be used in neighboring countries.Fil: Reza Yaghoobi Ershadi, Mohammad. Tehran University of Medical Sciences; IránFil: Akhavan, Amir Ahmad. Tehran University of Medical Sciences; IránFil: Reza Shirzadi, Mohammad. Iranian Ministry of Health and Medical Education; IránFil: Zohreh Hosseini, Seyedeh. Tehran University of Medical Sciences; IránFil: Salomón, Oscar Daniel. Secretaria de Gobierno de Salud. Instituto Nacional de Medicina Tropical. Instituto Nacional de Medicina Tropical - Sede Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Hanafi Bojd, Ahmad Ali. Tehran University of Medical Sciences; IránFil: Rassi, Yavar. Tehran University of Medical Sciences; Irá
Biochemical Basis of Cyfluthrin and DDT Resistance in Anopheles stephensi (Diptera: Culicidae) in Malarious Area of Iran
Background: Anopheles stephensi is a key urban malaria vector in the Indian subcontinent and Middle East including south and southeast of Iran. Wide application of insecticides resulted in resistance of this species to various insecticides in these regions. This study was conducted to reveal the role of metabolic mechanisms in the development of resistance in An. stephensi to DDT and cyfluthrin.
Methods: Field mosquito specimens were collected from Chabahar Seaport, southeast corner of Iran, in 2015. Insecticide susceptibility and enzyme assays were conducted as recommended by WHO.
Results: Mean enzyme ratios were 3.95 and 3.04 for α- esterases and 2.40 and 1.97 for β- esterases in the DDT and cyfluthrin- resistant populations correspondingly compared with the susceptible strain. The GSTs enzyme mean activity ratios were 5.07 and 2.55 in the DDT and cyfluthrin- resistant populations compared with the susceptible beech strain. The cytochrome p450s enzyme ratios were 1.11 and 1.28 in the DDT and cyfluthrin- resistant populations respectively compared with the susceptible beech strain.
Conclusion: Metabolic mechanisms play a crucial role in the development of DDT and cyfluthrin resistance in An. stephensi, therefore, further evaluation of the mechanisms involved as well as implementation of proper insecticide resistance management strategies are recommended
Laboratory Evaluation of Temephos against Anopheles stephensi and Culex pipiens Larvae in Iran
Background: Malaria is still a health problem in Iran. There are several vector control activities, including Indoor Residual spraying, using insecticide treated nets and larviciding including Temephos. In addition nuisance mosquitos are prevalent in the urban areas. So that evaluation of this species to larvicide will provide a clue for management of vector control activities.
Methods: Two mosquito species were used in this study: Anopheles stephensi were collected from Kazeroun and Culex pipiens from Tehran, capital of Iran. All the tests were carried out according to the WHO method. All the test kis was provided by WHO.
Results: Results showed a LC50= 0.0523 and LC90=0.3822 mg/l for An. stephensi. The figure for Cx. pipiens was 0.1838 and 0.8505 mg/l respectively.
Conclusions: monitoring of insecticide resistance to Temephos should be evaluated regularly for management of vector control
Fauna and some biological characteristics of Anopheles mosquitoes (Diptera: Culicidae) in Kalaleh County, Golestan Province, northeast of Iran
Objective: To determine fauna and some ecological aspects of Anopheles mosquitoes in northeast of Iran.
Methods: In this descriptive study, 3 villages in Kalaleh County were selected in different geographical zones. Anopheles mosquitoes were collected biweekly from May to October using standard dipping method for larvae, and hand catch, total catch, artificial pit shelter as well as night-biting collections on human and animal baits for adults.
Results: Totally 399 larvae and 2602 adults of Anopheles mosquitoes were collected and identified as 2 species: Anopheles superpictus s.l. (An. superpictus s.l.) and Anopheles maculipennis s.l. The dominant species was An. superpictus s.l. (92.1%). Activity of these mosquitoes found to be started from middle of May and extended till September with two peaks of activity in July and August.
Conclusions: An. superpictus s.l. as one of the main malaria vectors in Iran as well as some other parts of the world is the dominant species in the study area. This species has high potential for transmission and possibility of establishing a transmission cycle with low abundance. Other species, Anopheles maculipennis s.l. also has introduced as a malaria vector in northern parts of Iran. As this Anopheles is a complex species, genetic studies are recommended to determine the members of this complex in the study area
Bioecology of Dominant Malaria Vector, Anopheles superpictus s.l. Grassi (Diptera: Culicidae) In Iran
Background: Malaria continues to be a main vector-borne public health problem in Iran. The endemic foci of the disease are mainly located in south-eastern part of the country. Iran is now launching the elimination of malaria. Studies on the bioecology and susceptibility of malaria vectors to insecticide are essential in this phase.
Methods: The literature on bio-ecology of Anopheles superpictus s.l. Grassi was reviewed in Iran in more than half a century. Different aspects including, distribution, key identification, larval habitats, flight range, seasonal activities, irritability/susceptibility to insecticides, and anthropophilicity index were identified.
Results: The adult females of An. superpictus s.l. were susceptible to all WHO-recommended imagicides except DDT. Distribution, morphology, sibling species, larval habitat, flight range, Irritability tests, sustainability index, blood feeding preference and related factors were discussed in details
Conclusion: Results of the evaluating will help for decision making of authorities for vector control