Search results for: Jafar W. Al-Badarneh
17 MHD Stagnation Point Flow towards a Shrinking Sheet with Suction in an Upper-Convected Maxwell (UCM) Fluid
Authors: K. Jafar, R. Nazar, A. Ishak, I. Pop
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The present analysis considers the steady stagnation point flow and heat transfer towards a permeable sheet in an upper-convected Maxwell (UCM) electrically conducting fluid, with a constant magnetic field applied in the transverse direction to flow, and a local heat generation within the boundary layer with a heat generation rate proportional to (T-T_inf)^p. Using a similarity transformation, the governing system of partial differential equations is first transformed into a system of ordinary differential equations, which is then solved numerically using a finite-difference scheme known as the Keller-box method. Numerical results are obtained for the flow and thermal fields for various values of the shrinking/stretching parameter lambda, the magnetic parameter M, the elastic parameter K, the Prandtl number Pr, the suction parameter s, the heat generation parameter Q, and the exponent p. The results indicate the existence of dual solutions for the shrinking sheet up to a critical value lambda_c whose value depends on the value of M, K, and s. In the presence of internal heat absorbtion (Q<0), the surface heat transfer rate decreases with increasing p but increases with parameter Q and s, when the sheet is either stretched or shrunk.Keywords: magnetohydrodynamic (MHD), boundary layer flow, UCM fluid, stagnation point, shrinking sheet
Procedia PDF Downloads 35416 Effects of Nitroxin Fertilizer on Physiological Characters Forage Millet under Drought Stress Conditions
Authors: Mohammad Darbani, Jafar Masoud Sinaki, Armaghan Abedzadeh Neyshaburi
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An experiment was conducted as split plot factorial design using randomized complete block design in Damghan in 2012-2013 in order to investigate the effects of irrigation cut off (based on the Phenological stages of plants) on physiological properties of forage millet cultivars. The treatments included three irrigation levels (control with full irrigation, irrigation cut off when flowering started, and irrigation cut off when flowering ended) in the main plots, and applying nitroxin biofertilizer (+), not applying nitroxin biofertilizer (control), and Iranian forage millet cultivars (Bastan, Pishahang, and Isfahan) in the subplots. The highest rate of ashes and water-soluble carbohydrates content were observed in the cultivar Bastan (8.22 and 8.91%, respectively), the highest content of fiber and water (74.17 and 48.83%, respectively) in the treatment of irrigation cut off when flowering started, and the largest proline concentration (μmol/gfw-1) was seen in the treatment of irrigation cut off when flowering started. very rapid growth of millet, its short growing season, drought tolerance, its unique feature regarding harvest time, and its response to nitroxin biofertilizer can help expanding its cultivation in arid and semi-arid regions of Iran.Keywords: irrigation cut off, forage millet, Nitroxin fertilizer, physiological properties
Procedia PDF Downloads 60915 Effects of Tensile Pre-Stresses on Corrosion Behavior of AISI 304 Stainless Steel in 1N H2SO4
Authors: Sami Ibrahim Jafar, Israa Abud Alkadir, Samah Abdul Kareem Khashin
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The aim of this work is to assess the influence of tensile pre-stresses on the microstructure and corrosion behavior of the AISI304 stainless steel in 1N H2SO4 austenitic stainless steel. Samples of this stainless steel either with pre-stresses, corresponding to [255, 305, 355, 405, 455, 505, 555, 605 and σf] MPa induced by tensile tests, or without pre-stresses (as received), were characterized regarding their microstructure to investigate the pre-tensile stress effects on the corrosion behavior. The results showed that the corrosion rate of elastic pre-stresses 304 stainless steel was very little increased compared with that of as received specimens. The corrosion rate increases after applying pre-stress between (σ255 - σ 455) MPa. The microstructure showed that the austenitic grains begin to deform in the direction of applied pre-stresses. The maximum hardness at this region was (229.2) Hv, but at higher pre-stress (σ455 – σ 605) MPa unanticipated occurrence, the corrosion rate decreases. The microstructure inspection shows the deformed austenitic grain and ά-martensitic phase needle are appeared inside austenitic grains and the hardness reached the maximum value (332.433) Hv. The results showed that the corrosion rate increases at the values of pre-stresses between (σ605 – σf) MPa., which is inspected the result. The necking of gauge length of specimens occurs in specimens and this leads to deterioration in original properties and the corrosion rate reaches the maximum value.Keywords: tensile pre-stresses, corrosion rate, austenitic stainless steel, hardness
Procedia PDF Downloads 41114 Understanding the Factors That Enable Logistics Integration in the Port Sector: Evidence from Iranian Seaport Sector
Authors: Ali Alavi, Owen Nguyen, Jiangang Fei, Jafar Sayareh
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The main purpose of this research is to propose a conceptual framework to analyze port logistics integration in general and for the Iranian port sector in particular, including consideration of the challenges, outcomes, and opportunities in implementing port logistics integration. First, a literature review of studies on logistics integration in seaports and terminals is conducted. Second, a new conceptual framework for port logistics integration is proposed to incorporate the role of the new variables emerging from the recent developments in the global business environment. The literature review has found the logistics process and operations, information integration, value-added services, and logistics practices, organizational activities, resource sharing and institutional support being influential to logistics integration. The study used survey method to test the proposed conceptual framework. Both online and self-administrative survey have been used to collect data from port official staffs in Iranian seaports and their associations (internal port stakeholders) as well as other experts in various actors. In the study, the questionnaire was first validated using exploratory factor analysis (EFA) and then by confirmatory factor analysis (CFA). The results of the EFA and CFA confirmed the finding from the literature review. Research results and conceptual framework shed the lights on port logistics integration concept and suggest guidelines and procedures improve port logistics integration.Keywords: maritime logistics, logistics integration, port management, EFA, CFA
Procedia PDF Downloads 16313 An Investigation of the Effects of Emotional Experience Induction on Mirror Neurons System Activity with Regard to Spectrum of Depressive Symptoms
Authors: Elyas Akbari, Jafar Hasani, Newsha Dehestani, Mohammad Khaleghi, Alireza Moradi
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The aim of the present study was to assess the effect of emotional experience induction in the mirror neurons systems (MNS) activity with regard to the spectrum of depressive symptoms. For this purpose, at first stage, 449 students of Kharazmi University of Tehran were selected randomly and completed the second version of the Beck Depression Inventory (BDI-II). Then, 36 students with standard Z-score equal or above +1.5 and equal or equal or below -1.5 were selected to construct two groups of high and low spectrum of depressive symptoms. In the next stage, the basic activity of MNS was recorded (mu wave) before presenting the positive and negative emotional video clips by Electroencephalography (EEG) technique. The findings related to emotion induction (neutral, negative and positive emotion) demonstrated that the activity of recorded mirror neuron areas had a significant difference between the depressive and non-depressive groups. These findings suggest that probably processing of negative emotions in depressive individuals is due to the idea that the mirror neurons in motor cortex matched up the activity of cognitive regions with the person’s schema. Considering the results of the present study, it could be said that the MNS provides a substrate where emotional disorders can be studied and evaluated.Keywords: emotional experiences, mirror neurons, depressive symptoms, negative and positive emotion
Procedia PDF Downloads 35812 The Effect of Exposure to High Noise Level on the Performance and Rate of Error in Manual Activities
Authors: Zahra Zamanian, Alireza Zamanian, Jafar Hasanzadeh
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Background: Unwanted sound, as one of the most important physical factors in the majority of production units, imposes a great number of problems on the industrial workers. Sound is one of the environmental factors which can cause physical as well as psychological damages and also affects the individuals’ performance and productivity. Therefore, the present study aimed to determine the effect of noise exposure on human performance. Methods: The present study assessed the effect of noise on the performance of 50 students of Shiraz University of Medical Sciences (25 males and 25 females) at the sound pressures of 70, 90, and 110 dB by using two factors of physical features and the creation of different conditions of sound pressure source as well as applying Two-Arm coordination Test. Results: The results of the present study revealed no significant difference between male and female subjects as well as different conditions of creating sound pressure regarding the length of performance (p> 0.05). In addition, as the sound pressure increased, the length of performance increased, as well. According to the results, no significant difference was found between the performance at 70 and 90 dB. On the other hand, the performance at 110 dB was significantly different from the performance at 70 and 90 dB (p<0.05 and p<0.001). Conclusion: In general, as the sound pressure increases, the performance decreases which results in a considerable increase in the individuals’ rate of error.Keywords: physical factors, two-arm coordination test, Shiraz University of Medical Sciences, noise
Procedia PDF Downloads 30511 Enhanced Calibration Map for a Four-Hole Probe for Measuring High Flow Angles
Authors: Jafar Mortadha, Imran Qureshi
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This research explains and compares the modern techniques used for measuring the flow angles of a flowing fluid with the traditional technique of using multi-hole pressure probes. In particular, the focus of the study is on four-hole probes, which offer great reliability and benefits in several applications where the use of modern measurement techniques is either inconvenient or impractical. Due to modern advancements in manufacturing, small multi-hole pressure probes can be made with high precision, which eliminates the need for calibrating every manufactured probe. This study aims to improve the range of calibration maps for a four-hole probe to allow high flow angles to be measured accurately. The research methodology comprises a literature review of the successful calibration definitions that have been implemented on five-hole probes. These definitions are then adapted and applied on a four-hole probe using a set of raw pressures data. A comparison of the different definitions will be carried out in Matlab and the results will be analyzed to determine the best calibration definition. Taking simplicity of implementation into account as well as the reliability of flow angles estimation, an adapted technique from a research paper written in 2002 offered the most promising outcome. Consequently, the method is seen as a good enhancement for four-hole probes and it can substitute for the existing calibration definitions that offer less accuracy.Keywords: calibration definitions, calibration maps, flow measurement techniques, four-hole probes, multi-hole pressure probes
Procedia PDF Downloads 29510 Identification and Classification of Gliadin Genes in Iranian Diploid Wheat
Authors: Jafar Ahmadi, Alireza Pour-Aboughadareh
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Wheat is the first and the most important grain of the world and its bakery property is due to glutenin and gliadin qualities. Wheat seed proteins were divided into four groups according to solubility. Two groups are albumin and globulin dissolving in water and salt solutions possessing metabolic activities. Two other groups are inactive and non-dissolvable and contain glutelins or glutenins and prolamins or gliadins. Gliadins are major components of the storage proteins in wheat endosperm. Gliadin proteins are separated into three groups based on electrophoretic mobility: α/β-gliadin, γ-gliadin, and ω-gliadin. It seems that little information is available about gliadin genes in Iranian wild relatives of wheat. Thus, the aim of this study was the evaluation of the wheat wild relatives collected from different origins of Zagros Mountains in Iran, involving coding gliadin genes using specific primers. For this, forty accessions of Triticum boeoticum and Triticum urartu were selected. For each accession, genomic DNA was extracted and PCRs were performed in total volumes of 15 μl. The amplification products were separated on 1.5% agarose gels. In results, for Gli-2A locus, three allelic variants were detected by Gli-2As primer pairs. The sizes of PCR products for these alleles were 210, 490 and 700 bp. Only five (13%) and two accessions (5%) produced 700 and 490 bp fragments when their DNA was amplified with the Gli.As.2 primer pairs. However, 37 of the 40 accessions (93%) carried 210 bp allele, and three accessions (8%) did not yield any product for this marker. Therefore, these germplasm could be used as rich gene pool to broaden the genetic base of bread wheat.Keywords: diploied wheat, gliadin, Triticum boeoticum, Triticum urartu
Procedia PDF Downloads 2519 Port Logistics Integration: Challenges and Approaches: Case Study; Iranian Seaports
Authors: Ali Alavi, Hong-Oanh Nguyen, Jiangang Fei, Jafar Sayareh
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The recent competitive market in the port sector highly depend on logistics practices, functions and activities and seaports play a key role in port logistics chains. Despite the well-articulated importance of ports and terminals in integrated logistics, the role of success factors in port logistics integration has been rarely mentioned. The objective of this paper is to fill this gap in the literature and provide an insight into how seaports and terminals may improve their logistics integration. First, a literature review of studies on logistics integration in seaports and terminals is conducted. Second, a new conceptual framework for port logistics integration is proposed to incorporate the role of the new variables emerging from the recent developments in the global business environment. Third, the model tested in Iranian port and maritime sector using self-administered and online survey among logistics chain actors in Iranian seaports such shipping line operators, logistics service providers, port authorities, logistics companies and other related actors. The results have found the logistics process and operations, information integration, value-added services, and logistics practices being influential to logistics integration. A proposed conceptual framework is developed to extend the existing framework and incorporates the variables namely organizational activities, resource sharing, and institutional support. Further examination of the proposed model across multiple contexts is necessary for the validity of the findings. The framework could be more detailed on each factor and consider actors perspective.Keywords: maritime logistics, port integration, logistics integration, supply chain integration
Procedia PDF Downloads 2488 Catastrophic Spending on Health: A Determinant of Access to Health Care by Migrant Slum Population
Authors: Saira Mehnaz, Ali Jafar Abedi, Shazia Farooq Fazli, Sakeena Mushfiq, Zulfia Khan, M. Athar Ansari
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Introduction: Public health spending is a necessity in an underdeveloped country like India. The people are already suffering from poverty and that clubbed with out of pocket expenditure leads them to a very catastrophic situation, reducing the overall access to healthcare. Objectives: This study was designed to determine the usual source of medical care opted, the illness pattern, the expenditure incurred on illness and its source of procurement by the study population. It also intended to assess this expenditure as a determinant of access to health care. Methodology: Cities like Aligarh, which are classified as B grade cities in India are thought to be ripe sites for getting livelihood and hence are almost half filled with migrants living in urban slums. A cross sectional study was done to study the newer slum pockets. 3409 households with a population of 16,978 were studied with the help of pretested questionnaire; SPSS 20 was used for statistical analysis. Results and Conclusions: In our study, we found that almost all the households suffered from catastrophic health expenditure. The study population, which was already vulnerable owing to their low socio-economic and migrant status was further being forced with into poverty and indebtedness on account of expenditure on illness. This lead to a significant decrease in access to health. National health financing systems should be designed to protect households from financial catastrophe, by reducing out-of-pocket spending.Keywords: access to healthcare, catastrophic health expenditure, new urban slums, out of pocket expenditure
Procedia PDF Downloads 2077 Genome-Wide Analysis of BES1/BZR1 Gene Family in Five Plant Species
Authors: Jafar Ahmadi, Zhohreh Asiaban, Sedigheh Fabriki Ourang
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Brassinosteroids (BRs) regulate cell elongation, vascular differentiation, senescence and stress responses. BRs signal through the BES1/BZR1 family of transcription factors, which regulate hundreds of target genes involved in this pathway. In this research a comprehensive genome-wide analysis was carried out in BES1/BZR1 gene family in Arabidopsis thaliana, Cucumis sativus, Vitis vinifera, Glycin max, and Brachypodium distachyon. Specifications of the desired sequences, dot plot and hydropathy plot were analyzed in the protein and genome sequences of five plant species. The maximum amino acid length was attributed to protein sequence Brdic3g with 374aa and the minimum amino acid length was attributed to protein sequence Gm7g with 163aa. The maximum Instability index was attributed to protein sequence AT1G19350 equal with 79.99 and the minimum Instability index was attributed to protein sequence Gm5g equal with 33.22. Aliphatic index of these protein sequences ranged from 47.82 to 78.79 in Arabidopsis thaliana, 49.91 to 57.50 in Vitis vinifera, 55.09 to 82.43 in Glycin max, 54.09 to 54.28 in Brachypodium distachyon 55.36 to 56.83 in Cucumis sativus. Overall, data obtained from our investigation contributes a better understanding of the complexity of the BES1/BZR1 gene family and provides the first step towards directing future experimental designs to perform systematic analysis of the functions of the BES1/BZR1 gene family.Keywords: BES1/BZR1, brassinosteroids, phylogenetic analysis, transcription factor
Procedia PDF Downloads 3396 The Hepatoprotective Effects of Aquatic Extract of Levesticum Officinale against Paraquat Toxicity of Hepatocytes
Authors: Hasan Afarnegan, Ali Shahraki, Jafar Shahraki
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Paraquat is widely used as a strong nitrogen-based herbicide for controlling of weeds in agriculture. This poison is extremely toxic for humans which induces several – organ failure by accumulation in cells and many instances of death occurred due to its poisoning. Paraquat metabolized primarily in the liver. The purpose of this study was to assess the effects of aquatic extract of levisticum officinale on oxidative status and biochemical factors in hepatocytes exposed to paraquat. Our results determined that hepatocytes destruction induced by paraquat is mediated by reactive oxygen species (ROS) production, lipid peroxidation and decrease of mitochondrial membrane potential were significantly (P<0.05) prevented by aquatic extract of Levisicum officinale (100, 200 and 300 µg/ml). These effects of paraquat also prevented via antioxidants and ROS scavengers (α-tocopherol, DMSO, manitol), mitochondrial permeability transition (MPT) pore sealing compound (carnitine).MPT pore sealing compound inhibited the hepatotoxicity, indicating that paraquat induced cell death via mithochondrial pathway. Pretreatment of hepatocytes with aquatic extracts of Levisticum officinale, antioxidants and ROS scavengers also blocked hepatic cell death caused by paraquat, suggesting that oxidative stress may be directly induced decline of mithochondrial membrane potential. In conclusion, paraquat hepatotoxicity can be attributed to oxidative stress and continued by mithochondrial membrane potential disruption. Levisticum officinale aquatic extract, presumably due to its strong antoxidant properties, could protect the destructive effects of paraquat on rat hepatocytes.Keywords: hepatocyte protection, levisticum officinale, oxidative stress, paraquat
Procedia PDF Downloads 2225 Assessment of Heavy Metal Bioaccumulation by Tissues of Ipomoea Batatas and Manihot Esculenta Irrigated with Water from Muhammad Ayuba Dam, Kazaure, Jigawa State, Nigeria
Authors: Sa’idu A. Abdullah, Jafar Lawan, A. U. Adamu, Fowotade, S. A., Hamisu Abdu
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Scarcity of quality water in many communities compels inhabitants to use any available water resources for domestic, recreational, industrial and agricultural purposes. Global concern on the potential health hazards of anthropogenic inputs into our ecosystems imposes the need for constant monitoring of levels of pollutants in order to ensure compliance with internationally acceptable criteria. In this research, assessment of bioaccumulation of Cd, Co, Cu, Pb and Zn was carried out using tissues of Ipomoea batatas (sweet potato) and Manihot esculenta (cassava) irrigated with water from Muhammad Ayuba Dam in Kazaure, Jigawa State. The metal concentrations were determined using Flame Atomic Absorption Spectrophotometer (FAAS). The result of the analysis revealed the presence of the metals in varying concentrations. Cd and Co showed higher concentrations in the tubers of Manihot esculenta but all the other investigated metals were more concentrated in the leaves of the plant. Cd and Cu on the other hand showed higher concentration in the root of Ipomoea batatas while the remaining investigated metals were concentrated more in the leaves of the plant. The result of analysis of water samples from five sampling stations in the Dam showed the presence of the metals as follows: Cd, (0.063±0.02 mg/L), Co (0.086±0.03 mg/L), Cu (0.167±0.08 mg/L), Pb (0.22±0.01 mg/L) and Zn (0.047±0.01 mg/L) respectively. The results of bioaccumulation studies using the Bioaccumulation Factors (BAF) index indicated Ipomoea batatas to have higher bioaccumulation potential for Cd, Co and Cu while Pb and Zn were more accumulated in Manihot esculenta. The levels of the metals in both the water samples and plant tissues were all below the WHO permissible limit. This is indicative that the inhabitants of the community under investigation are not at any health risk.Keywords: agriculture, bioaccumulation, heavy metal, plant tissues
Procedia PDF Downloads 3854 Sulfonic Acid Functionalized Ionic Liquid in Combinatorial Approach: A Recyclable and Water Tolerant-Acidic Catalyst for Friedlander Quinoline Synthesis
Authors: Jafar Akbari
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Quinolines are very important compounds partially because of their pharmacological properties which include wide applications in medicinal chemistry. notable among them are antimalarial drugs, anti-inflammatory agents, antiasthamatic, antibacterial, antihypertensive, and tyrosine kinase inhibiting agents. Despite quinoline usage in pharmaceutical and other industries, comparatively few methods for their preparation have been reported.The Friedlander annulation is one of the simplest and most straightforward methods for the synthesis of poly substituted quinolines. Although, modified methods employing lewis or br¢nsted acids have been reported for the synthesis of quinolines, the development of water stable acidic catalyst for quinoline synthesis is quite desirable. One of the most remarkable features of ionic liquids is that the yields can be optimized by changing the anions or the cations. Recently, sulfonic acid functionalized ionic liquids were used as solvent-catalyst for several organic reactions. We herein report the one pot domino approach for the synthesis of quinoline derivatives in Friedlander manner using TSIL as a catalyst. These ILs are miscible in water, and their homogeneous system is readily separated from the reaction product, combining advantages of both homogeneous and heterogeneous catalysis. In this reaction, the catalyst plays a dual role; it ensures an effective condensation and cyclization of 2-aminoaryl ketone with second carbonyl group and it also promotes the aromatization to the final product. Various types of quinolines from 2-aminoaryl ketones and β-ketoesters/ketones were prepared in 85-98% yields using the catalytic system of SO3-H functionalized ionic liquid/H2O. More importantly, the catalyst could be easily recycled for five times without loss of much activity.Keywords: antimalarial drugs, green chemistry, ionic liquid, quinolines
Procedia PDF Downloads 2103 Design and Analysis of a Combined Cooling, Heating and Power Plant for Maximum Operational Flexibility
Authors: Salah Hosseini, Hadi Ramezani, Bagher Shahbazi, Hossein Rabiei, Jafar Hooshmand, Hiwa Khaldi
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Diversity of energy portfolio and fluctuation of urban energy demand establish the need for more operational flexibility of combined Cooling, Heat, and Power Plants. Currently, the most common way to achieve these specifications is the use of heat storage devices or wet operation of gas turbines. The current work addresses using variable extraction steam turbine in conjugation with a gas turbine inlet cooling system as an alternative way for enhancement of a CCHP cycle operating range. A thermodynamic model is developed and typical apartments building in PARDIS Technology Park (located at Tehran Province) is chosen as a case study. Due to the variable Heat demand and using excess chiller capacity for turbine inlet cooling purpose, the mentioned steam turbine and TIAC system provided an opportunity for flexible operation of the cycle and boosted the independence of the power and heat generation in the CCHP plant. It was found that the ratio of power to the heat of CCHP cycle varies from 12.6 to 2.4 depending on the City heating and cooling demands and ambient condition, which means a good independence between power and heat generation. Furthermore, selection of the TIAC design temperature is done based on the amount of ratio of power gain to TIAC coil surface area, it was found that for current cycle arrangement the TIAC design temperature of 15 C is most economical. All analysis is done based on the real data, gathered from the local weather station of the PARDIS site.Keywords: CCHP plant, GTG, HRSG, STG, TIAC, operational flexibility, power to heat ratio
Procedia PDF Downloads 2812 Heavy Metals and Carcinogenic Risk Assessment in Free-Ranged Livestock of Lead-Contaminated Goldmine Communities of Zamfara State, Northern Nigeria
Authors: Sulaiman Rabiu, Muazu Gusau Abubakar, Jafar Usman Zakari
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The consumption of meat is of great importance as it provides a good source of proteins and significant amount of essential trace element to the body. However, contamination of meat and meat products with heavy metals is becoming a serious threat to food safety and public health. Therefore, the present study is aimed to evaluate the concentration of some heavy metals in muscles and entrails of free-ranged cattle, sheep and goats. A total of sixty (60) fresh samples of muscles, liver, kidney, small intestines and stomach of free ranged cattle, sheep and goats were collected from abattoirs of different goldmine communities of Anka, Bukkuyum, Maru andTalata-Mafara Local Government Areas of Zamfara State, Nigeria. The samples were digested using 10 mL of a mixed 70% high grade concentration of HNO₃ and 65% HCl (4:1 v/v); the mixture was heated until dense fumes disappeared forming a clear transparent solution and diluted to 50 mL with deionized water. Actual concentrations of Cd, Cr, Cu, Co, As, Ni, Mn, Pb and Zn were determined using Microwave Plasma Atomic Emission Spectrophotometer (MP-AES). From the results obtained, goat liver had the highest mean concentration of lead, arsenic, cobalt and manganese (12.43± 0.31, 14.25±0.32, 3.47± 0.86 and 12.68± 0.92 mg/kg respectively) while goat kidney had the highest concentration of copper and zinc (10.08±0.61 and 24.16±1.30 mg/kg respectively). The highest concentrations of cadmium and nickel were recorded in sheep kidney (7.75± 0.65 and 2.08±0.10 mg/kg respectively). Cattle muscles had the highest chromium concentration than all the organs analysed. The target hazard quotients (THQs) for all the metals were below 1.0, but TR which is a risk indices for carcinogenicity indicates an alarming result that requires stringent control to protect public health.Therefore, intensive public health awareness on the risk associated with contamination of heavy metals in meat should be advocated.Keywords: contamination, goldmine, heavy metals, meat
Procedia PDF Downloads 1101 Detection of Glyphosate Using Disposable Sensors for Fast, Inexpensive and Reliable Measurements by Electrochemical Technique
Authors: Jafar S. Noori, Jan Romano-deGea, Maria Dimaki, John Mortensen, Winnie E. Svendsen
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Pesticides have been intensively used in agriculture to control weeds, insects, fungi, and pest. One of the most commonly used pesticides is glyphosate. Glyphosate has the ability to attach to the soil colloids and degraded by the soil microorganisms. As glyphosate led to the appearance of resistant species, the pesticide was used more intensively. As a consequence of the heavy use of glyphosate, residues of this compound are increasingly observed in food and water. Recent studies reported a direct link between glyphosate and chronic effects such as teratogenic, tumorigenic and hepatorenal effects although the exposure was below the lowest regulatory limit. Today, pesticides are detected in water by complicated and costly manual procedures conducted by highly skilled personnel. It can take up to several days to get an answer regarding the pesticide content in water. An alternative to this demanding procedure is offered by electrochemical measuring techniques. Electrochemistry is an emerging technology that has the potential of identifying and quantifying several compounds in few minutes. It is currently not possible to detect glyphosate directly in water samples, and intensive research is underway to enable direct selective and quantitative detection of glyphosate in water. This study focuses on developing and modifying a sensor chip that has the ability to selectively measure glyphosate and minimize the signal interference from other compounds. The sensor is a silicon-based chip that is fabricated in a cleanroom facility with dimensions of 10×20 mm. The chip is comprised of a three-electrode configuration. The deposited electrodes consist of a 20 nm layer chromium and 200 nm gold. The working electrode is 4 mm in diameter. The working electrodes are modified by creating molecularly imprinted polymers (MIP) using electrodeposition technique that allows the chip to selectively measure glyphosate at low concentrations. The modification included using gold nanoparticles with a diameter of 10 nm functionalized with 4-aminothiophenol. This configuration allows the nanoparticles to bind to the working electrode surface and create the template for the glyphosate. The chip was modified using electrodeposition technique. An initial potential for the identification of glyphosate was estimated to be around -0.2 V. The developed sensor was used on 6 different concentrations and it was able to detect glyphosate down to 0.5 mgL⁻¹. This value is below the accepted pesticide limit of 0.7 mgL⁻¹ set by the US regulation. The current focus is to optimize the functionalizing procedure in order to achieve glyphosate detection at the EU regulatory limit of 0.1 µgL⁻¹. To the best of our knowledge, this is the first attempt to modify miniaturized sensor electrodes with functionalized nanoparticles for glyphosate detection.Keywords: pesticides, glyphosate, rapid, detection, modified, sensor
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