Search results for: biological and chemical treatment
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 13171

Search results for: biological and chemical treatment

9811 Exploring the Biocompatibility and Performance of Metals and Ceramics as Biomaterials, A Comprehensive Study for Advanced Medical Applications

Authors: Ala Abobakr Abdulhafidh Al-Dubai

Abstract:

Biomaterials, specifically metals and ceramics, are indispensable components in the realm of medical science, shaping the landscape of implantology and prosthetics. This study delves into the intricate interplay between these materials and biological systems, aiming to scrutinize their suitability, performance, and biocompatibility. Employing a multi-faceted approach, a range of methodologies were meticulously employed to comprehensively characterize these biomaterials. Advanced material characterization techniques were paramount in this research, with scanning electron microscopy providing intricate insights into surface morphology, and X-ray diffraction unraveling the crystalline structures. These analyses were complemented by in vitro assessments, which gauged the biological response of cells to metals and ceramics, shedding light on their potential applications within the human body. A key facet of our investigation involved a comparative study, evaluating the corrosion resistance and osseointegration potential of both metals and ceramics. Through a series of experiments, we sought to understand how these biomaterials interacted with physiological environments, paving the way for informed decisions in medical applications

Keywords: metals, ceramics, biomaterials, biocompatibility, osseointegration

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9810 Comparison of Different in vitro Models of the Blood-Brain Barrier for Study of Toxic Effects of Engineered Nanoparticles

Authors: Samir Dekali, David Crouzier

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Due to their new physico-chemical properties engineered nanoparticles (ENPs) are increasingly employed in numerous industrial sectors (such as electronics, textile, aerospace, cosmetics, pharmaceuticals, food industry, etc). These new physico-chemical properties can also represent a threat for the human health. Consumers can notably be exposed involuntarily by different routes such as inhalation, ingestion or through the skin. Several studies recently reported a possible biodistribution of these ENPs on the blood-brain barrier (BBB). Consequently, there is a great need for developing BBB in vitro models representative of the in vivo situation and capable of rapidly and accurately assessing ENPs toxic effects and their potential translocation through this barrier. In this study, several in vitro models established with micro-endothelial brain cell lines of different origins (bEnd.3 mouse cell line or a new human cell line) co-cultivated or not with astrocytic cells (C6 rat or C8-B4 mouse cell lines) on Transwells® were compared using different endpoints: trans-endothelial resistance, permeability of the Lucifer yellow and protein junction labeling. Impact of NIST diesel exhaust particles on BBB cell viability is also discussed.

Keywords: nanoparticles, blood-brain barrier, diesel exhaust particles, toxicology

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9809 Chemical Partitioning of Trace Metals in Sub-Surface Sediments of Lake Acigol, Denizli, Turkey

Authors: M. Budakoglu, M. Karaman, D. Kiran, Z. Doner, B. Zeytuncu, B. Tanç, M. Kumral

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Lake Acıgöl is one of the large saline lacustrine environment in Turkey. Eleven trace metals (Cr, Mn, Fe, Al, Co, Ni, Cu, Zn, Cd, Pb and As) in 9 surface and subsurface sediment samples from the Lake Acıgöl were analyzed with the bulk and sequential extraction analysis methods by ICP-MS to obtain the metal distribution patterns in this extreme environment. Five stepped sequential extraction technique (1- exchangeable, 2- bond to carbonates, 3- bond to iron and manganese oxides/hydroxides, 4- bond to organic matter and sulphides, and 5- residual fraction incorporated into clay and silicate mineral lattices) was used to characterize the various forms of metals in the <63μ size sediments. The metal contents (ppm) and their percentages for each extraction step were reported and compared with the results obtained from the total digestion. Results indicate that sum of the four fraction are in good agreement with the total digestion results of Ni, Cd, As, Zn, Cu and Fe with the satisfactory recoveries (94.04–109.0%) and the method used is reliable and repeatable for these elements. It was found that there were high correlations between Fe vs. Ni loads in the fraction of F2 and F4 with R2= 0,91 and 0,81, respectively. Comparison of totally 135 chemical analysis results in three sampling location and for 5 fraction between Fe-Co, Co-Ni and Fe-Ni element couples were presented elevated correlations with R2=0,98, 0,92 and 0,91, respectively.

Keywords: Lake Acigol, sequancial extraction, recent lake sediment, geochemical speciation of heavy metals

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9808 The Behavior of Dam Foundation Reinforced by Stone Columns: Case Study of Kissir Dam-Jijel

Authors: Toufik Karech, Abderahmen Benseghir, Tayeb Bouzid

Abstract:

This work presents a 2D numerical simulation of an earth dam to assess the behavior of its foundation after a treatment by stone columns. This treatment aims to improve the bearing capacity, to increase the mechanical properties of the soil, to accelerate the consolidation, to reduce the settlements and to eliminate the liquefaction phenomenon in case of seismic excitation. For the evaluation of the pore pressures, the position of the phreatic line and the flow network was defined, and a seepage analysis was performed with the software MIDAS Soil Works. The consolidation calculation is performed through a simulation of the actual construction stages of the dam. These analyzes were performed using the Mohr-Coulomb soil model and the results are compared with the actual measurements of settlement gauges implanted in the dam. An analysis of the bearing capacity was conducted to show the role of stone columns in improving the bearing capacity of the foundation.

Keywords: earth dam, dam foundation, numerical simulation, stone columns, seepage analysis, consolidation, bearing capacity

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9807 Effect of Rhythmic Auditory Stimulation on Gait in Patients with Stroke

Authors: Mohamed Ahmed Fouad

Abstract:

Background: Stroke is the most leading cause to functional disability and gait problems. Objectives: The purpose of this study was to determine the effect of rhythmic auditory stimulation combined with treadmill training on selected gait kinematics in stroke patients. Methods: Thirty male stroke patients participated in this study. The patients were assigned randomly into two equal groups, (study and control). Patients in the study group received treadmill training combined with rhythmic auditory stimulation in addition to selected physical therapy program for hemiparetic patients. Patients in the control group received treadmill training in addition to the same selected physical therapy program including strengthening, stretching, weight bearing, balance exercises and gait training. Biodex gait trainer 2 TM was used to assess selected gait kinematics (step length, step cycle, walking speed, time on each foot and ambulation index) before and after six weeks training period (end of treatment) for both groups. Results: There was a statistically significant increase in walking speed, step cycle, step length, percent of the time on each foot and ambulation index in both groups post-treatment. The improvement in gait parameters post-treatment was significantly higher in the study group compared to the control. Conclusion: Rhythmic auditory stimulation combined with treadmill training is effective in improving selected gait kinematics in stroke patients when added to the selected physical therapy program.

Keywords: stroke, rhythmic auditory stimulation, treadmill training, gait kinematics

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9806 Anal Repair and Diamond Flap in Moderate Anal Stenosis Patient After an Open Hemorrhoidectomy Surgery: A Case Report

Authors: Andriana Purnama, Reno Rudiman, Kezia Christy

Abstract:

Anal stenosis which develops due to anoderm scarring usually caused by secondary to surgical trauma, has become common, causing significant decrease patient’s quality of life. Even though mild anal stenosis was treated with non-surgical treatment, but surgical reconstruction in unavoidable for moderate to severe anal stenosis that cause distressing, severe anal pain and inability to defecate. In our study, we intend to share our result with the use of diamond flap in treatment of anal stenosis. This case report illustrates a 57-year-old male patient who presented with difficulty and discomfort in defecation caused by anal stenosis after 2 years of open hemorrhoidectomy surgery. At physical examination, there was requirement of forceful dilatation when the index finger was inserted or precisely 6mm as measured by hegar dilator (moderate anal stenosis). Blood test result was within normal limits. The patient underwent anal repair and diamond flap where the scar tissue at 6 and 9 o’clock directions was excised and diamond graft was incised carefully while paying attention to the vascular supply. Finally, the graft was fixated without any tension to the anal canal, resulting in diameter of 2 cm after operation. After 2 days post operation, the patient was in stable condition, without any complication, and discharged. There was no abnormality concerning the stool. Ten days after the operation, diamond flap was in normal condition and without any complication. He was scheduled for futher follow up at the Digestive Surgery Department. Anal stenosis due to overzealous hemorrhoidectomy is a complication that is preventable when performed in experienced hands. Diamond flap was one of the options for the anal stenosis treatment with less complication.

Keywords: anal stenosis, diamond flap, post hemorrhoidectomy, anal repair

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9805 Identification of Active Phytocomponents in the Ethyl Acetate Extract of Glycosmis pentaphylla Retz. DC by Using GC-MS

Authors: M. Sivakumar, D. Chamundeeswari

Abstract:

Glycosmis pentaphylla is one of the medicinally important plants belonging to the family Rutaceae, commonly known as “Anam or Panal” in Tamil. Traditionally, leaves are useful in fever, hepatopathy, eczema, skin disease, helminthiasis, wounds, and erysipelas. The fruits are sweet and are useful in vitiated conditions of vata, kapha, cough, and bronchitis. The roots are good for facial inflammations, rheumatism, jaundice, and anemia. The preliminary phytochemical investigations indicated the presence of alkaloids, terpenoids, flavonoids, tannins, sugar, glycoside, and phenolic compounds. In the present study, the root part of Glycosmis pentaphylla was used, and the root was collected from Western Ghats of South India. The root was sun/shade dried and pulverized to powder in a mechanical grinder. The powder was successively extracted with various solvents, and the ethyl acetate extract of Glycosmis pentaphylla has been subjected to the GC-MS analysis. Amongst the 46 chemical constituents identified from this plant, three major phytoconstituents were reported for the first time. Marmesin, a furanocumarin compound with the chemical structure 7H-Furo (3,2-G) (1)Benzopyran-7-one,2,3–dihydro–2 - (1-Hydroxy-1methylethyl)-(s) is one of the three compounds identified for the first time at the concentration of 11-60% in ethyl acetate extract of Glycosmis pentaphylla. Others include, Beta.-Fagarine (4.71%) and Paverine (13.08%).

Keywords: ethyl acetate extract, Glycosmis pentaphylla, GC-MS analysis, Phytochemicals

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9804 Effects of Nicotine on Symptoms Associated with Attention Deficit Hyperactivity Disorder: A Systematic Literature Review

Authors: Daniella Hirwa

Abstract:

Attention Deficit Hyperactivity Disorder (ADHD) is associated with several risk-taking behaviors, including drug use and smoking. Such risk-taking behaviors are often a result of an attempt to self-manage symptoms associated with ADHD. The present review investigates the effects of nicotine on symptoms associated with ADHD. This systematic literature review was conducted for 2017-2024 using keywords associated with ADHD, smoking, and nicotine. The results indicate that individuals with ADHD start smoking earlier than those without ADHD, and it is believed that this prevalence and the higher rates of smoking are due to improvements in cognitive and executive function, attention, and impulsivity due to the effect that nicotine has on dopamine release. Longitudinal studies with larger sample sizes and comprehensive health history and cognitive testing are required to gain more insight into the ways that nicotine affects ADHD symptoms and the context by which smoking is used as a method of self-treatment to help aid the development of nicotine-based treatment options that do not pose the same health risks as smoking.

Keywords: ADHD, nicotine, risk-taking behaviors, smoking

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9803 Induction of HIV-1 Resistance: The New Approaches Based on Gene Modification and Stem Cell Engineering

Authors: Alieh Farshbaf

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Introduction: Current anti-retroviral drugs have some restrictions for treatment of HIV-1 infection. The efficacy of retroviral drugs is not same in different infected patients and the virus rebound from latent reservoirs after stopping them. Recently, the engineering of stem cells and gene therapy provide new approaches to eliminate some drug problems by induction of resistance to HIV-1. Literature review: Up to now, AIDS-restriction genes (ARGs) were suitable candidate for gene and cell therapies, such as cc-chemokine receptor-5 (CCR5). In this manner, CCR5 provide effective cure in Berlin and Boston patients by inducing of HIV-1 resistance with allogeneic stem cell transplantation. It is showed that Zinc Finger Nuclease (ZFN) could induce HIV-1 resistance in stem cells of infected patients by homologous recombination or non-end joining mechanism and eliminate virus loading after returning the modified cells. Then, gene modification by HIV restriction factors, as TRIM5, introduced another gene candidate for HIV by interfering in infection process. These gene modifications/editing provided by stem cell futures that improve treatment in refractory disease such as HIV-1. Conclusion: Although stem cell transplantation has some complications, but in compare to retro-viral drugs demonstrated effective cure by elimination of virus loading. On the other hand, gene therapy is cost-effective for an infected patient than retroviral drugs payment in a person life-long. The results of umbilical cord blood stem cell transplantation showed that gene and cell therapy will be applied easier than previous treatment of AIDS with high efficacy.

Keywords: stem cell, AIDS, gene modification, cell engineering

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9802 Determination of Critical Period for Weed Control in the Second Crop Forage Maize (454 Cultivar)

Authors: Farhad Farahvash, Parya Mobaseri

Abstract:

Weeds control based on their critical period leads to less production costs and risks of wide chemical application of weeds control methods. The present study considered effect of weeds control time (weeds interference after 20, 40 and 60 days, weeds full control, weeds interference and weeds control after 20, 40 and 60 days) on growth and yield of forage maize 454. The experiment based on full-randomized blocks design with three replications was conducted at research farm of Islamic Azad University of Tabriz located at 15th km of East Tabriz in 2013. According to the results, weeds interference after 40 and 60 days as well as weeds control after 20 days prevented from decrease of maize biomass resulted from weeds presence while weeds interference after 20 days, weeds interference and weeds control after 40 and 60 days led respectively to 41.2%, 35%, 25% and 32.5% decrease of forage maize biomass. The weeds-influenced decrease was manifested at different parts of the plant depending on presence period of weeds. Decrease of fresh weight of ear and fresh weight of leaf and stem was observed due to weeds interference after 20 days and weeds interference. If weeds are controlled after 60 days, decrease of ear weight and fresh weight of stem will lead to biomass decrease. Also, if weeds are controlled after 40 days, decrease of fresh weight of maize stems will result in biomass decrease. Ear traits were affected by weeds control treatment. Being affected by treatments of weeds interference after 20 days, weeds non-interference, weeds control after 40 and 60 days, ear length was shortened 29.9 %, 41.4 %, 27.6 % and 37.2 %, respectively. The stem diameter demonstrated a significant decrease although it was only affected by treatments of weeds interference and weeds control after 60 days. Considering results of the present study, generally, it is suggested to control weeds during initial 20-60 days of maize growth in order to prevent undesirable effect of weeds on growth, production and production biomass of maize and decrease of production costs.

Keywords: maize, competition, weed, biomass

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9801 Biosynthesis of Silver Nanoparticles Using Zataria multiflora Extract, and Study of Antibacterial Effects on UTI Bacteria (MDR)

Authors: Mohammad Hossein Pazandeh, Monir Doudi, Sona Rostampour Yasouri

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Irregular consumption of current antibiotic makes increases of antibiotic resistance between urin pathogens on all worlds. This study selected based on this great community problem. The aim of this study was the biosynthesis of silver nanoparticles from Zataria multiflora extract and then to investigate its antibacterial effect on gram-negative bacilli common in Urinary Tract Infections (UTI) and MDR. The plant used in the present research was Zataria multiflora whose extract was prepared through Soxhlet extraction method. Green synthesis condition of silver nanoparticles was investigated in terms of three parameters including the extract amount, concentration of silver nitrate salt, and temperature. The seizes of nanoparticles were determined by Zetasizer. In order to identify synthesized silver nanoparticles Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) methods were used. For evaluating the antibacterial effects of nanoparticles synthesized through biological method different concentrations of silver nanoparticles were studied on 140 cases of Muliple Drug Resistance (MDR) bacteria strains Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Proteus vulgaris,Citrobacter freundii, Acinetobacter bumanii and Pseudomonas aeruginosa, (each genus of bacteria, 20 samples), which all were MDR and cause urinary tract infections , for identification of bacteria were used of Polymerase Chain Reaction (PCR) test and laboratory methods (Agar well diffusion and Microdilution methods) to assess their sensitivity to Nanoparticles. The data were analyzed using SPSS software by nonparametric Kruskal-Wallis and Mann-Whitney tests. Significant results were found about the effects of silver nitrate concentration, different amounts of Zataria multiflora extract, and temperature on nanoparticles; that is, by increasing the concentration of silver nitrate, extract amount, and temperature, the sizes of synthesized nanoparticles declined. However, the effect of above mentioned factors on particles diffusion index was not significant. Based on the TEM results, particles were mainly spherical shape with a diameter range of 25 to 50 nm. The results of XRD Analysis indicated the formation of Nanostructures and Nanocrystals of silver.. The obtained results of antibacterial effects of different concentrations of silver nanoparticles on according to agar well diffusion and microdilution method, biologically synthesized nanoparticles showed 1000 mg /ml highest and lowest mean inhibition zone diameter in E.coli , Acinetobacter bumanii 23 and 15mm, respectively. MIC was observed for all of bacteria 125mg/ml and for Acinetobacter bumanii 250mg/ml.Comparing the growth inhibitory effect of chemically synthesized Nanoparticles and biologically synthesized Nanoparticles showed that in the chemical method the highest growth inhibition belonged to the concentration of 62.5 mg /ml. The inhibitory effect on the growth all of bacteria causes of urine infection and MDR was observed and by increasing silver ion concentration in Nanoparticles, antibacterial activity increased. Generally, the biological synthesis can be considered an efficient way not only in making Nanoparticles but also for having anti-bacterial properties. It is more biocompatible and may be possess less toxicity than the Nanoparticles synthesized chemically.

Keywords: biosynthesis, MDR bacteria, silver nanoparticles, UTI

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9800 Chemical and Mineralogical Properties of Soils from an Arid Region of Misurata-Libya: Treated Wastewater Irrigation Impacts

Authors: Khalifa Alatresh, Mirac Aydin

Abstract:

This research explores the impacts of irrigation by treated wastewater (TWW) on the mineralogical and chemical attributes of sandy calcareous soils in the Southern region of Misurata. Soil samples obtained from three horizons (A, B, and C) of six TWW-irrigated pedons (29years) and six other pedons from nearby non-irrigated areas (dry-control). The results demonstrated that the TWW-irrigated pedons had significantly higher salinity (EC), sodium adsorption ratio (SAR), exchangeable sodium percentage (ESP), cation exchange capacity (CEC), available phosphor (AP), total nitrogen (TN), and organic matter (OM) relative to the control pedons. Nonetheless, all the values of interest (EC < 4000 µs/cm < SAR < 13, pH < 8.5 and ESP < 15) remained lower than the thresholds, showing no issues with sodicity or salinity. Irrigated pedons contained significantly higher amounts of total clay and showed an altered distribution of particle sizes and minerals identified (quartz, calcite, microcline, albite, anorthite, and dolomite) within the profile. The observed results included the occurrence of Margarite, Anorthite, Chabazite, and Tridymite minerals after the application of TWW in small quantities that are not enough to influence soil genesis and classification.0,51 cm.

Keywords: treated wastewater, sandy calcareous soils, soil mineralogy, and chemistry

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9799 Implementation of IWA-ASM1 Model for Simulating the Wastewater Treatment Plant of Beja by GPS-X 5.1

Authors: Fezzani Boubaker

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The modified activated sludge model (ASM1 or Mantis) is a generic structured model and a common platform for dynamic simulation of varieties of aerobic processes for optimization and upgrading of existing plants and for new facilities design. In this study, the modified ASM1 included in the GPS-X software was used to simulate the wastewater treatment plant (WWTP) of Beja treating domestic sewage mixed with baker‘s yeast factory effluent. The results of daily measurements and operating records were used to calibrate the model. A sensitivity and an automatic optimization analysis were conducted to determine the most sensitive and optimal parameters. The results indicated that the ASM1 model could simulate with good accuracy: the COD concentration of effluents from the WWTP of Beja for all months of the year 2012. In addition, it prevents the disruption observed at the output of the plant by injecting the baker‘s yeast factory effluent at high concentrations varied between 20 and 80 g/l.

Keywords: ASM1, activated sludge, baker’s yeast effluent, modelling, simulation, GPS-X 5.1 software

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9798 A Cognitive Behavioural Therapy for Post-Traumatic Stress Disorders

Authors: Ryotaro Ishikawa

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INTRODUCTION: Post-traumatic stress disorder (PTSD) is a psychiatric label for a collection of psychological symptoms following a traumatic event. PTSD is as a result of a traumatic experience such as rape or sexual assault. A victim may have PTSD if she/he has experienced the following symptoms for at least a month: a) Stressor, b) Intrusion symptoms, c) Avoidance, d) Negative alterations in cognitions and mood, e) Alterations in arousal and reactivity. Studies on the cognitive theory of PTSD emphasized the roles of (a) negative appraisals of trauma memories in maintaining the symptomatology of PTSD, and (b) disorganized trauma memories in the development of PTSD. Mental contamination is primarily caused by experiences involving humans (e.g. violators or perpetrators) as opposed to substances (e.g. dirt or bodily fluids). Feelings of mental contamination may evoke following experiences of ill-treatment, sexual assault, domination, degradation, manipulation, betrayal, or humiliation. Some studies have demonstrated that traumatic thoughts related to sexual assault are particularly strong predictors of mental contamination. Treatment protocols based on cognitive-behavioral therapy appear to be beneficial in reducing the severity of PTSD and mental contamination. Studies on the cognitive theory of PTSD emphasized the roles of (A) negative appraisals of trauma memories in maintaining the symptomatology of PTSD, and (B) disorganized trauma memories in the development of PTSD. We will demonstrate a feasibility study of individual CBT for PTSD and mental contamination in Japanese clinical settings. METHOD: The single-arm trial is a group setting CBT intervention. The primary outcome is the self-rated Posttraumatic Stress Diagnostic Scale, with secondary measurements of depressive severity and mental pollution questionnaire. Assessments are conducted at baseline, after a waiting period before CBT, during CBT, and after CBT. RESULTS: Participants are eligible for the study and complete the outcome measures at all assessment points. In our hypothesis, receiving CBT would lead to improvements in primary and secondary PTSD severity. CONCLUSION: We will demonstrate a feasibility study of individual CBT for PTSD and mental contamination in Japanese clinical settings. Our treatment would achieve favorable treatment outcomes for PTSD with mental contamination in Japanese clinical settings.

Keywords: CBT, cognitive theory, PTSD, mental pollution

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9797 Entomopathogenic Bacteria as Biological Control Agents: Review Paper

Authors: Tadesse Kebede Dabsu

Abstract:

Insect pest is one the major limiting factor for sustainable food production. To overtake insect pest problem, since Second World War, producers have used excessive insecticide for insect pest management. However, in the era of 21st Century, the excessive use of insecticide caused insect resistant, insecticide bioaccumulation, insecticide hazard to environment, human health problem, and the like. Due to these problems, research efforts have been focused on the development of environmental free sustainable insect pest management method. To minimize all above mentioned risk utilizing of biological control such as entomopathogenicmicroorganism include bacteria, virus, fungus, and their productsare the best option for suppress insect population below certain density level. The objective of this review was to review the updated available studies and recent developments on the entomopathogenic bacteria (EPB) as biological control of insect pest and challenge of using them for control of insect pest. EPB’s mechanisms of insecticidal activities, type, taxonomy, and history are included in this paper body. EPB has been successfully used for the suppression of populations of insect pests. Controlling of harmful insect by entomopathogenic bacteria is an effective, low bioaccumulation in environment and food, very specific, reduce resistance risk in insect pest, economically and sustainable method of major insect pest management method. Identified and reported as potential major common type of entomopathogenic bacteria include Bacillus thuringiensis, Photorhabdus sp., Xenorhabdus spp.Walbachiaspp, Actinomycetesspp.etc. These bacteria being enter into insect body through natural opening or by vector release toxin protein inside of insect and disrupt the cell’s content cause natural mortality under natural condition. As per reported by different scientists, insect orders like Lepidoptera, Hemiptera, Hymenoptera, Coleoptera, and Dipterahave been successful controlled by entomopathogenic bacteria. As per coming across in different scientific research journals, much of the work was emphasised on Bacillus thuringiensisbsp. Therefore, for commercial production like Bacillus thuringiensi, detail research should be done on other bacteria species. The efficacy and practical application of EPB are restricted to some crops and greenhouse area, but their field application at farmers’ level very less. So still much work needs to be done to the practical application of the EPB at widely application. Their efficacy, pathogenicity, and host range test should be tested under environmental condition.

Keywords: insect pest, entomopathogenic bacteria, biological control, agent

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9796 Delineation of Oil– Polluted Sites in Ibeno LGA, Nigeria

Authors: Ime R. Udotong, Ofonime U. M. John, Justina I. R. Udotong

Abstract:

Ibeno, Nigeria hosts the operational base of Mobil Producing Nigeria Unlimited (MPNU), a subsidiary of ExxonMobil and the current highest oil and condensate producer in Nigeria. Besides MPNU, other multinational oil companies like Shell Petroleum Development Company Ltd, Elf Petroleum Nigeria Ltd and Nigerian Agip Energy, a subsidiary of ENI E&P operate onshore, on the continental shelf and deep offshore of the Atlantic Ocean in Ibeno, Nigeria, respectively. This study was designed to carry out the survey of the oil impacted sites in Ibeno, Nigeria. A combinations of electrical resistivity (ER), ground penetrating radar (GPR) and physico-chemical as well as microbiological characterization of soils and water samples from the area were carried out. Results obtained revealed that there have been hydrocarbon contaminations of this environment by past crude oil spills as observed from significant concentrations of THC, BTEX and heavy metal contents in the environment. Also, high resistivity values and GPR profiles clearly showing the distribution, thickness and lateral extent of hydrocarbon contamination as represented on the radargram reflector tones corroborates previous significant oil input. Contaminations were of varying degrees, ranging from slight to high, indicating levels of substantial attenuation of crude oil contamination over time. Hydrocarbon pollution of the study area was confirmed by the results of soil and water physico-chemical and microbiological analysis. The levels of THC contamination observed in this study are indicative of high levels of crude oil contamination. Moreover, the display of relatively lower resistivities of locations outside the impacted areas compared to resistivity values within the impacted areas, the 3-D Cartesian images of oil contaminant plume depicted by red, light brown and magenta for high, low and very low oil impacted areas, respectively as well as the high counts of hydrocarbonoclastic microorganisms in excess of 1% confirmed significant recent pollution of the study area.

Keywords: oil-polluted sites, physico-chemical analyses, microbiological characterization, geotechnical investigations, total hydrocarbon content

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9795 Use of Thermosonication to Obtain Minimally Processed Mosambi Juice

Authors: Ruby Siwach, Manish Kumar, Raman Seth

Abstract:

Extent of inactivation of pectin methylesterase (PME) in mosambi juice during thermal and thermosonication treatments was studied to obtain a minimally processed product. Effect of both treatments on cloud value, pH, titratable acidity, oBrix, and sensory attributes (flavour and taste) was studied. Thermal treatments (HT) were carried out at three temperatures 60, 70, and 80°C in a serological water bath for 5, 10, 15, and 20 min at each temperature. Thermosonication treatments (TS) were also given for same time-temperature combinations in water bath of a thermosonicator. Treated samples were stored in a deep freezer at 18°C for PME assay. PME activity of untreated sample was also assayed and residual PME activity and % loss in PME activity was calculated at each time-temperature combination. The extent of inactivation of PME increased with increase in treatment temperature and duration. Thermosonication treatments were found far more effective than thermal treatments of same time temperature combination in PME inactivation and retention of sensory attributes.

Keywords: pectin methylesterase, heat inactivation kinetics, thermosonication, thermal treatment

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9794 Polypyrrole as Bifunctional Materials for Advanced Li-S Batteries

Authors: Fang Li, Jiazhao Wang, Jianmin Ma

Abstract:

The practical application of Li-S batteries is hampered due to poor cycling stability caused by electrolyte-dissolved lithium polysulfides. Dual functionalities such as strong chemical adsorption stability and high conductivity are highly desired for an ideal host material for a sulfur-based cathode. Polypyrrole (PPy), as a conductive polymer, was widely studied as matrixes for sulfur cathode due to its high conductivity and strong chemical interaction with soluble polysulfides. Thus, a novel cathode structure consisting of a free-standing sulfur-polypyrrole cathode and a polypyrrole coated separator was designed for flexible Li-S batteries. The PPy materials show strong interaction with dissoluble polysulfides, which could suppress the shuttle effect and improve the cycling stability. In addition, the synthesized PPy film with a rough surface acts as a current collector, which improves the adhesion of sulfur materials and restrain the volume expansion, enhancing the structural stability during the cycling process. For further enhancing the cycling stability, a PPy coated separator was also applied, which could make polysulfides into the cathode side to alleviate the shuttle effect. Moreover, the PPy layer coated on commercial separator is much lighter than other reported interlayers. A soft-packaged flexible Li-S battery has been designed and fabricated for testing the practical application of the designed cathode and separator, which could power a device consisting of 24 light-emitting diode (LED) lights. Moreover, the soft-packaged flexible battery can still show relatively stable cycling performance after repeated bending, indicating the potential application in flexible batteries. A novel vapor phase deposition method was also applied to prepare uniform polypyrrole layer coated sulfur/graphene aerogel composite. The polypyrrole layer simultaneously acts as host and adsorbent for efficient suppression of polysulfides dissolution through strong chemical interaction. The density functional theory (DFT) calculations reveal that the polypyrrole could trap lithium polysulfides through stronger bonding energy. In addition, the deflation of sulfur/graphene hydrogel during the vapor phase deposition process enhances the contact of sulfur with matrixes, resulting in high sulfur utilization and good rate capability. As a result, the synthesized polypyrrole coated sulfur/graphene aerogel composite delivers a specific discharge capacity of 1167 mAh g⁻¹ and 409.1 mAh g⁻¹ at 0.2 C and 5 C respectively. The capacity can maintain at 698 mAh g⁻¹ at 0.5 C after 500 cycles, showing an ultra-slow decay rate of 0.03% per cycle.

Keywords: polypyrrole, strong chemical interaction, long-term stability, Li-S batteries

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9793 Evaluation of Mechanical Properties and Analysis of Rapidly Heat Treated M-42 High Speed Steel

Authors: R. N. Karthik Babu, R. Sarvesh, A. Rajendra Prasad, G. Swaminathan

Abstract:

M42 is a molybdenum-series high-speed alloy steel widely used because of its better hot-hardness and wear resistance. These steels are conventionally heat treated in a salt bath furnace with up to three stages of preheating with predetermined soaking and holding periods. Such methods often involve long periods of processing with a large amount of energy consumed. In this study, the M42 steel samples were heat-treated by rapidly heating the specimens to the austenising temperature of 1260 °C and cooled conventionally by quenching in a neutral salt bath at a temperature of 550 °C with the aid of a hybrid microwave furnace. As metals reflect microwaves, they cannot directly be heated up when placed in a microwave furnace. The technology used herein requires the specimens to be placed in a crucible lined with SiC which is a good absorber of microwaves and the SiC lining heats the metal through radiation which facilitates the volumetric heating of the metal. A sample of similar dimensions was heat treated conventionally and cooled in the same manner. Conventional tempering process was then carried out on both these samples and analysed for various parameters such as micro-hardness, processing time, etc. Microstructure analysis and scanning electron microscopy was also carried out. The objective of the study being that similar or better properties, with substantial time and energy saving and cost cutting are achievable by rapid heat treatment through hybrid microwave furnaces. It is observed that the heat treatment is done with substantial time and energy savings, and also with minute improvement in mechanical properties of the tool steel heat treated.

Keywords: rapid heating, heat treatment, metal processing, microwave heating

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9792 Surface Coatings of Boards Made from Alternative Materials

Authors: Stepan Hysek, Petra Gajdacova

Abstract:

In recent years, alternative materials, such as annual plants or recycled and waste materials are becoming more and more popular input material for the production of composite materials. They can be used for the production of insulation boards, construction boards or furniture boards. Surface finishing of those boards is essential for utilization in furniture. However, some difficulties could occur during coating of boards from alternative materials; physical and chemical differences from conventional particleboards need to be considered. From the physical aspects, surface soundness and surface roughness mainly determine the quality of the surface. Since surface layers of boards from alternative materials have often lower density, these characteristics could be deteriorated and thus the production process needs to be optimized. Also, chemical reactions of board’s material with coating could be undesirable. The objective of this study is to evaluate the parameters affecting the surface quality of boards made form alternative materials and to find possibilities of the coating of these boards. In this study, boards of particles from rapeseed stems were produced using a laboratory press. Surface soundness, as representatives of mechanical properties and surface roughness, as representative of physical properties, were measured on boards from rapeseed stems. Results clearly indicated that produced boards had lower surface quality than commercially produced particle boards from wood. Therefore, higher thickness of surface coating on rapeseed based boards is needed.

Keywords: coating, surface, annual plant, composites, particleboard

Procedia PDF Downloads 265
9791 Anti-Inflammatory Studies of Grewia crenata Leaves Extract in Albino Rats

Authors: A. N. Ukwuani, M. G. Abubakar, S. W. Hassan

Abstract:

Grewia crenata is used locally in the treatment of fractured bones, wound healing and inflammatory conditions. The anti-inflammatory activity of hydromethanolic extract of G. crenata leaves was investigated using egg albumin induced-hind paw oedema model in albino rat. The extract produced a time-dependent inhibition of egg albumin induced-hind paw oedema at 30th minutes up to 150th minutes in all the groups compared to the control. Significant reduction (p<0.05) of hind paw oedema was observed 150 minutes after egg albumin injection. The percentage inhibition produced by the extract at 200 mg/kg (22.1%) was comparable to that produced by 10 mg/kg indomethacin (24.9%) at the 150th minutes of post-egg albumin injection. Preliminary qualitative phytochemical analysis revealed the presence of saponins, steroids, flavonoids, anthraquinones and glycosides. The results obtained in this study suggest that Grewia crenata can be a potential source of anti-inflammatory agent and validates its use in the treatment of inflammatory conditions.

Keywords: Grewia crenata, anti-inflammatory, hind paw, oedema

Procedia PDF Downloads 310
9790 Review of Numerical Models for Granular Beds in Solar Rotary Kilns for Thermal Applications

Authors: Edgar Willy Rimarachin Valderrama, Eduardo Rojas Parra

Abstract:

Thermal energy from solar radiation is widely present in power plants, food drying, chemical reactors, heating and cooling systems, water treatment processes, hydrogen production, and others. In the case of power plants, one of the technologies available to transform solar energy into thermal energy is by solar rotary kilns where a bed of granular matter is heated through concentrated radiation obtained from an arrangement of heliostats. Numerical modeling is a useful approach to study the behavior of granular beds in solar rotary kilns. This technique, once validated with small-scale experiments, can be used to simulate large-scale processes for industrial applications. This study gives a comprehensive classification of numerical models used to simulate the movement and heat transfer for beds of granular media within solar rotary furnaces. In general, there exist three categories of models: 1) continuum, 2) discrete, and 3) multiphysics modeling. The continuum modeling considers zero-dimensional, one-dimensional and fluid-like models. On the other hand, the discrete element models compute the movement of each particle of the bed individually. In this kind of modeling, the heat transfer acts during contacts, which can occur by solid-solid and solid-gas-solid conduction. Finally, the multiphysics approach considers discrete elements to simulate grains and a continuous modeling to simulate the fluid around particles. This classification allows to compare the advantages and disadvantages for each kind of model in terms of accuracy, computational cost and implementation.

Keywords: granular beds, numerical models, rotary kilns, solar thermal applications

Procedia PDF Downloads 34
9789 Effects of Collection Time on Chemical Composition of Leaf Essential Oils of Hoslundia opposita

Authors: O. E. Ogunjinmi, N. O. Olawore, L. A. Usman, S. O. Ogunjinmi

Abstract:

An essential oil is any concentrated, hydrophobic liquid containing volatile aroma compounds produced by plants. It has been established that several factors affect the component of the plants such as the texture of the soil, relative humidity, wind, and collection time. This study is aimed at investigating the effect of collection time on the chemical composition of this essential oil. Pulverized leaves (500 g) of Hoslundia opposite harvested in the morning (7 am) and afternoon (2 pm) of the same day were separately hydrodistilled using Clevenger apparatus to obtain the essential oils from the leaves. The leaf oils collected in the morning (7 am) and afternoon (2 pm) harvests yielded 0.54 and 0.65 %w/w respectively. Analysis of the leaf oil obtained in the morning, using gas chromatography (GC) and gas chromatography combined mass spectrometry (GC-MS) revealed the presence of twenty-three (23) compounds which made up 81.8% of the total oil while nineteen (19) compounds (93.2%) were identified in the afternoon leaf essential oil. The most abundant components of the leaf oil collected in the morning (7 am) harvest were p-cymene (28.7%), sabinene (7.1%) and 1,8-cineole (6.6%) Meanwhile the major components of leaf oil in the afternoon (2 pm) harvest were p-cymene (26.4%), thymol (15.3%), 1,8-cineole (15.0%) and g-terpinene (10.4%). The composition pattern of leaf oil obtained in the morning and afternoon harvests of Hoslundia opposite revealed significant differences in qualitative and quantitative.

Keywords: essential oil, Hoslundia opposita, para cymene, 1, 8-cineole

Procedia PDF Downloads 391
9788 Superficial Metrology of Organometallic Chemical Vapour Deposited Undoped ZnO Thin Films on Stainless Steel and Soda-Lime Glass Substrates

Authors: Uchenna Sydney Mbamara, Bolu Olofinjana, Ezekiel Oladele B. Ajayi

Abstract:

Elaborate surface metrology of undoped ZnO thin films, deposited by organometallic chemical vapour deposition (OMCVD) technique at different precursor flow rates, was carried out. Dicarbomethyl-zinc precursor was used. The films were deposited on AISI304L steel and soda-lime glass substrates. Ultraviolet-visible-near-infrared (UV-Vis-NIR) spectroscopy showed that all the thin films were over 80% transparent, with an average bandgap of 3.39 eV, X-ray diffraction (XRD) results showed that the thin films were crystalline with a hexagonal structure, while Rutherford backscattering spectroscopy (RBS) results identified the elements present in each thin film as zinc and oxygen in the ratio of 1:1. Microscope and contactless profilometer results gave images with characteristic colours. The profilometer also gave the surface roughness data in both 2D and 3D. The asperity distribution of the thin film surfaces was Gaussian, while the average fractal dimension Da was in the range of 2.5 ≤ Da. The metrology proved the surfaces good for ‘touch electronics’ and coating mechanical parts for low friction.

Keywords: undoped ZnO, precursor flow rate, OMCVD, thin films, surface texture, tribology

Procedia PDF Downloads 62
9787 Verification of Dosimetric Commissioning Accuracy of Flattening Filter Free Intensity Modulated Radiation Therapy and Volumetric Modulated Therapy Delivery Using Task Group 119 Guidelines

Authors: Arunai Nambi Raj N., Kaviarasu Karunakaran, Krishnamurthy K.

Abstract:

The purpose of this study was to create American Association of Physicist in Medicine (AAPM) Task Group 119 (TG 119) benchmark plans for flattening filter free beam (FFF) deliveries of intensity modulated radiation therapy (IMRT) and volumetric arc therapy (VMAT) in the Eclipse treatment planning system. The planning data were compared with the flattening filter (FF) IMRT & VMAT plan data to verify the dosimetric commissioning accuracy of FFF deliveries. AAPM TG 119 proposed a set of test cases called multi-target, mock prostate, mock head and neck, and C-shape to ascertain the overall accuracy of IMRT planning, measurement, and analysis. We used these test cases to investigate the performance of the Eclipse Treatment planning system for the flattening filter free beam deliveries. For these test cases, we generated two sets of treatment plans, the first plan using 7–9 IMRT fields and a second plan utilizing two arc VMAT technique for both the beam deliveries (6 MV FF, 6MV FFF, 10 MV FF and 10 MV FFF). The planning objectives and dose were set as described in TG 119. The dose prescriptions for multi-target, mock prostate, mock head and neck, and C-shape were taken as 50, 75.6, 50 and 50 Gy, respectively. The point dose (mean dose to the contoured chamber volume) at the specified positions/locations was measured using compact (CC‑13) ion chamber. The composite planar dose and per-field gamma analysis were measured with IMatriXX Evaluation 2D array with OmniPro IMRT Software (version 1.7b). FFF beam deliveries of IMRT and VMAT plans were comparable to flattening filter beam deliveries. Our planning and quality assurance results matched with TG 119 data. AAPM TG 119 test cases are useful to generate FFF benchmark plans. From the obtained data in this study, we conclude that the commissioning of FFF IMRT and FFF VMAT delivery were found within the limits of TG-119 and the performance of the Eclipse treatment planning system for FFF plans were found satisfactorily.

Keywords: flattening filter free beams, intensity modulated radiation therapy, task group 119, volumetric modulated arc therapy

Procedia PDF Downloads 146
9786 A Measurement Instrument to Determine Curricula Competency of Licensure Track Graduate Psychotherapy Programs in the United States

Authors: Laith F. Gulli, Nicole M. Mallory

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We developed a novel measurement instrument to assess Knowledge of Educational Programs in Professional Psychotherapy Programs (KEP-PPP or KEP-Triple P) within the United States. The instrument was designed by a Panel of Experts (PoE) that consisted of Licensed Psychotherapists and Medical Care Providers. Licensure track psychotherapy programs are listed in the databases of the Commission on Accreditation for Marriage and Family Therapy Education (COAMFTE); American Psychological Association (APA); Council on Social Work Education (CSWE); and the Council for Accreditation of Counseling & Related Educational Programs (CACREP). A complete list of psychotherapy programs can be obtained from these professional databases, selecting search fields of (All Programs) in (All States). Each program has a Web link that electronically and directly connects to the institutional program, which can be researched using the KEP-Triple P. The 29-item KEP Triple P was designed to consist of six categorical fields; Institutional Type: Degree: Educational Delivery: Accreditation: Coursework Competency: and Special Program Considerations. The KEP-Triple P was designed to determine whether a specific course(s) is offered in licensure track psychotherapy programs. The KEP-Triple P is designed to be modified to assess any part or the entire curriculum of licensure graduate programs. We utilized the KEP-Triple P instrument to study whether a graduate course in Addictions was offered in Marriage and Family Therapy (MFT) programs. Marriage and Family Therapists are likely to commonly encounter patients with Addiction(s) due to the broad treatment scope providing psychotherapy services to individuals, couples and families of all age groups. Our study of 124 MFT programs which concluded at the end of 2016 found that we were able to assess 61 % of programs (N = 76) since 27 % (N = 34) of programs were inaccessible due to broken Web links. From the total of all MFT programs 11 % (N = 14) did not have a published curriculum on their Institutional Web site. From the sample study, we found that 66 % (N = 50) of curricula did not offer a course in Addiction Treatment and that 34 % (N =26) of curricula did require a mandatory course in Addiction Treatment. From our study sample, we determined that 15 % (N = 11) of MFT doctorate programs did not require an Addictions Treatment course and that 1 % (N = 1) did require such a course. We found that 99 % of our study sample offered a Campus based program and 1 % offered a hybrid program with both online and residential components. From the total sample studied, we determined that 84 % of programs would be able to obtain reaccreditation within a five-year period. We recommend that MFT programs initiate procedures to revise curricula to include a required course in Addiction Treatment prior to their next accreditation cycle, to improve the escalating addiction crisis in the United States. This disparity in MFT curricula raises serious ethical and legal consideration for national and Federal stakeholders as well as for patients seeking a competently trained psychotherapist.

Keywords: addiction, competency, curriculum, psychotherapy

Procedia PDF Downloads 151
9785 Investigation of Effective Parameters on Water Quality of Iranian Rivers Using Hydrochemical and Statistical Methods

Authors: Maryam Sayadi, Rana Sedighpour, Hossein Rezaie

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In this study, in order to evaluate water quality of Gamasiab and Gharehsoo rivers located in Kermanshah province, the information of a 5-year statistical period during the years 2014-2018 was used. To evaluate the hydrochemistry of water, first the type and hydrogeochemical facies of river water were determined using Stiff and Piper diagrams. Then, based on Gibbs diagram and combination diagrams, the factors controlling the chemical parameters of the two rivers were identified. Saturation indices were used to predict the possibility of dissolution and deposition of some minerals. Then, in order to classify water in different sections, fourteen water quality indicators for different uses along with WHO standard were used. Finally, factor analysis was used to determine the processes affecting the hydrochemistry of the two rivers. The results of this study showed that in both rivers, the predominant type and facies are bicarbonate of calcite. Also, the main factor in changing the chemical quality of water in both Gamasiab and Gharehsoo rivers is the water-rock reaction. According to the results of factor analysis in both rivers, two factors have the greatest impact on water quality in the region. Among the parameters of Gamasiab river in the first factor, HCO3-, Na+ and Cl-, respectively, had the highest factor loads, and in the second factor, SO42- and Mg2+ were selected as the main parameters. The parameters Ca2+, Cl- and Na have the highest factor loads in the first factor and in the second factor Mg2+ and SO42- have the highest factor loads in Gharehsoo river. The dissolution of carbonate formations due to their abundance and expansion in the two basins has a more significant effect on changing water chemistry. It has saturated the water of rivers with aragonite, calcite and dolomite. Due to the low contribution of the second factor in changing the chemical parameters, the water of both rivers is saturated with respect to evaporative minerals such as gypsum, halite and anhydrite in all stations. Based on Schoeller diagrams, Wilcox and other quality indicators in these two sections, the amount of main physicochemical parameters are in the desired range for drinking and agriculture. The results of Langelier, Ryznar, Larson-Skold and Puckorius indices showed that water is corrosive in industry.

Keywords: factor analysis, hydrochemical, saturation index, surface water quality

Procedia PDF Downloads 126
9784 Competitivity in Procurement Multi-Unit Discrete Clock Auctions: An Experimental Investigation

Authors: Despina Yiakoumi, Agathe Rouaix

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Laboratory experiments were run to investigate the impact of different design characteristics of the auctions, which have been implemented to procure capacity in the UK’s reformed electricity markets. The experiment studies competition among bidders in procurement multi-unit discrete descending clock auctions under different feedback policies and pricing rules. Theory indicates that feedback policy in combination with the two common pricing rules; last-accepted bid (LAB) and first-rejected bid (FRB), could affect significantly the auction outcome. Two information feedback policies regarding the bidding prices of the participants are considered; with feedback and without feedback. With feedback, after each round participants are informed of the number of items still in the auction and without feedback, after each round participants have no information about the aggregate supply. Under LAB, winning bidders receive the amount of the highest successful bid and under the FRB the winning bidders receive the lowest unsuccessful bid. Based on the theoretical predictions of the alternative auction designs, it was decided to run three treatments. First treatment considers LAB with feedback; second treatment studies LAB without feedback; third treatment investigates FRB without feedback. Theoretical predictions of the game showed that under FRB, the alternative feedback policies are indifferent to the auction outcome. Preliminary results indicate that LAB with feedback and FRB without feedback achieve on average higher clearing prices in comparison to the LAB treatment without feedback. However, the clearing prices under LAB with feedback and FRB without feedback are on average lower compared to the theoretical predictions. Although under LAB without feedback theory predicts the clearing price will drop to the competitive equilibrium, experimental results indicate that participants could still engage in cooperative behavior and drive up the price of the auction. It is showed, both theoretically and experimentally, that the pricing rules and the feedback policy, affect the bidding competitiveness of the auction by providing opportunities to participants to engage in cooperative behavior and exercise market power. LAB without feedback seems to be less vulnerable to market power opportunities compared to the alternative auction designs. This could be an argument for the use of LAB pricing rule in combination with limited feedback in the UK capacity market in an attempt to improve affordability for consumers.

Keywords: descending clock auctions, experiments, feedback policy, market design, multi-unit auctions, pricing rules, procurement auctions

Procedia PDF Downloads 298
9783 An Alternative Antimicrobial Approach to Fight Bacterial Pathogens from Phellinus linteus

Authors: S. Techaoei, K. Jarmkom, P. Eakwaropas, W. Khobjai

Abstract:

The objective of this research was focused on investigating in vitro antimicrobial activity of Phellinus linteus fruiting body extracts on Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus. Phellinus linteus fruiting body was extracted with ethanol and ethyl acetate and was vaporized. The disc diffusion assay was used to assess antimicrobial activity against tested bacterial strains. Primary screening of chemical profile of crude extract was determined by using thin layer chromatography. The positive control and the negative control were used as erythromycin and dimethyl sulfoxide, respectively. Initial screening of Phellinus linteus crude extract with the disc diffusion assay demonstrated that only ethanol had greater antimicrobial activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus. The MIC assay showed that the lower MIC was observed with 0.5 mg/ml of Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus and 0.25 mg/ml. of Escherichia coli and Staphylococcus aureus, respectively. TLC chemical profile of extract was represented at Rf ≈ 0.71-0.76.

Keywords: Staphylococcus aureus, Escherichia coli, Phellinus linteus, Methicillin-resistant Staphylococcus aureus, antimicrobial activity

Procedia PDF Downloads 284
9782 Effect of Chemical Fertilizer on Plant Growth-Promoting Rhizobacteria in Wheat

Authors: Tessa E. Reid, Vanessa N. Kavamura, Maider Abadie, Adriana Torres-Ballesteros, Mark Pawlett, Ian M. Clark, Jim Harris, Tim Mauchline

Abstract:

The deleterious effect of chemical fertilizer on rhizobacterial diversity has been well documented using 16S rRNA gene amplicon sequencing and predictive metagenomics. Biofertilization is a cost-effective and sustainable alternative; improving strategies depends on isolating beneficial soil microorganisms. Although culturing is widespread in biofertilization, it is unknown whether the composition of cultured isolates closely mirrors native beneficial rhizobacterial populations. This study aimed to determine the relative abundance of culturable plant growth-promoting rhizobacteria (PGPR) isolates within total soil DNA and how potential PGPR populations respond to chemical fertilization in a commercial wheat variety. It was hypothesized that PGPR will be reduced in fertilized relative to unfertilized wheat. Triticum aestivum cv. Cadenza seeds were sown in a nutrient depleted agricultural soil in pots treated with and without nitrogen-phosphorous-potassium (NPK) fertilizer. Rhizosphere and rhizoplane samples were collected at flowering stage (10 weeks) and analyzed by culture-independent (amplicon sequence variance (ASV) analysis of total rhizobacterial DNA) and -dependent (isolation using growth media) techniques. Rhizosphere- and rhizoplane-derived microbiota culture collections were tested for plant growth-promoting traits using functional bioassays. In general, fertilizer addition decreased the proportion of nutrient-solubilizing bacteria (nitrate, phosphate, potassium, iron and, zinc) isolated from rhizocompartments in wheat, whereas salt tolerant bacteria were not affected. A PGPR database was created from isolate 16S rRNA gene sequences and searched against total soil DNA, revealing that 1.52% of total community ASVs were identified as culturable PGPR isolates. Bioassays identified a higher proportion of PGPR in non-fertilized samples (rhizosphere (49%) and rhizoplane (91%)) compared to fertilized samples (rhizosphere (21%) and rhizoplane (19%)) which constituted approximately 1.95% and 1.25% in non-fertilized and fertilized total community DNA, respectively. The analyses of 16S rRNA genes and deduced functional profiles provide an in-depth understanding of the responses of bacterial communities to fertilizer; this study suggests that rhizobacteria, which potentially benefit plants by mobilizing insoluble nutrients in soil, are reduced by chemical fertilizer addition. This knowledge will benefit the development of more targeted biofertilization strategies.

Keywords: bacteria, fertilizer, microbiome, rhizoplane, rhizosphere

Procedia PDF Downloads 307