Search results for: substrate concentration
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5724

Search results for: substrate concentration

1434 Potentially Toxic Cyanobacteria and Quantification of Microcystins/Nodularins and Cylindspermopsine in Four Dams of Guanajuato, Mexico

Authors: Laura Valdés-Santiago, José Luis Castro-Guillén, Jorge Noé García-Chávez, Rosalba Alonso-Rodríguez, Rafael Vargas-Bernal

Abstract:

The quality and availability of the water contained in dams (artificial bodies of water) are at risk due to the presence of uncontrolled growths of cyanobacteria capable of producing cyanotoxins that affect the ecosystem and harm the health of humans and animals. The physicochemical properties were measured, and the degree of eutrophy of four dams from Guanajuato was determined. They presented a pH of 6.1 to 8.4, conductivity of 121 to 415 μS/cm², chlorophyll of 0.43-42.43 μg/L, NO₃- 0-1.2 mg/L and PO₄3- 0.11 to 0.84 mg/L; considering these parameters, the prey most prone to the development of cyanobacterial blooms were El Palote dam, La Purísima dam, and Allende dam, but not El Conejo dam. The potentially toxic cyanobacteria identified were Planktothrix agardhii, Oscillatoria sp., Raphidiopsis sp., and Microcystis sp., Microcystin-LR, Nodularin, and Cylindrospermopsin were quantified, presenting values between 0.08-0.42 and 0.02-2.05 ppb, respectively, the water bodies with the highest concentration were El Palote dam and La Purísima dam. Microcystin-LR and/or Nodularin levels are within the guideline values for human consumption in drinking water established by the World Health Organization for Microcystin-LR and for Cylindrospermopsin by the Oregon Health Authority (OHA) in all dams. This work is relevant due to the use of these bodies of water for agriculture and human consumption in the state, and the presence of toxin-producing cyanobacteria can represent an environmental, ecotoxicological, and health problem, so it is recommended to establish a program of frequent monitoring of cyanobacteria and cyanotoxins in the state's dams.

Keywords: Planktrothrix agardhii, Raphidiopsis sp., Microcystis sp., Cyanobacterial blooms, Cyanotoxins

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1433 Stimulation of Stevioside Accumulation on Stevia rebaudiana (Bertoni) Shoot Culture Induced with Red LED Light in TIS RITA® Bioreactor System

Authors: Vincent Alexander, Rizkita Esyanti

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Leaves of Stevia rebaudiana contain steviol glycoside which mainly comprise of stevioside, a natural sweetener compound that is 100-300 times sweeter than sucrose. Current cultivation method of Stevia rebaudiana in Indonesia has yet to reach its optimum efficiency and productivity to produce stevioside as a safe sugar substitute sweetener for people with diabetes. An alternative method that is not limited by environmental factor is in vitro temporary immersion system (TIS) culture method using recipient for automated immersion (RITA®) bioreactor. The aim of this research was to evaluate the effect of red LED light induction towards shoot growth and stevioside accumulation in TIS RITA® bioreactor system, as an endeavour to increase the secondary metabolite synthesis. The result showed that the stevioside accumulation in TIS RITA® bioreactor system induced with red LED light for one hour during night was higher than that in TIS RITA® bioreactor system without red LED light induction, i.e. 71.04 ± 5.36 μg/g and 42.92 ± 5.40 μg/g respectively. Biomass growth rate reached as high as 0.072 ± 0.015/day for red LED light induced TIS RITA® bioreactor system, whereas TIS RITA® bioreactor system without induction was only 0.046 ± 0.003/day. Productivity of Stevia rebaudiana shoots induced with red LED light was 0.065 g/L medium/day, whilst shoots without any induction was 0.041 g/L medium/day. Sucrose, salt, and inorganic consumption in both bioreactor media increased as biomass increased. It can be concluded that Stevia rebaudiana shoot in TIS RITA® bioreactor induced with red LED light produces biomass and accumulates higher stevioside concentration, in comparison to bioreactor without any light induction.

Keywords: LED, Stevia rebaudiana, Stevioside, TIS RITA

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1432 Preventive Effect of Zinc on Nickel Hepatotoxicity and Nephrotoxicity in Albino (Wistar) Rats

Authors: Zine Kechrid, Samira Bouhalit

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Aim: We studied the effect of intraperitonial zinc treatment on nickel sulphate-induced hepatotoxicity and nephrotoxicity in Wistar strain male albino rats. Materials and Methods: Liver and kidney dysfunction parameters represented by aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), blood glucose, serum total protein, serum urea, serum creatinine, and serum belurebin were estimated. Liver glutathione level, catalase and GPx activities were also determined in liver as indicators of oxidative damage. Result: Nickel treatment led to high serum glucose concentration and produced hepatotoxicity and nephrotoxicity characterized by increasing GPT, GOT and alkaline phosphatase activities, serum total protein, serum urea, serum creatinine and serum belurebin concentrations. In addition, liver glutathione level, catalase and GSH-Px activities diminished due to high lipid peroxidation. The simultaneous administration of zinc with nickel sulphate resulted in a remarkable improvement of the previous parameters compared with rats treated with nickel alone. Conclusion: In conclusion, nickel sulphate led to liver and kidney dysfunctions and hepatic lipid peroxidation in animals, but simultaneous treatment with zinc offers a relative protection against nickel induced hepatotoxicity, nephrotoxicity and lipid peroxidation.

Keywords: nickel, zinc, rats, GOT, GPT, nephrotoxicity, hepatotoxicity

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1431 Fish Scales as a Nonlethal Screening Tools for Assessing the Effects of Surface Water Contaminants in Cyprinus Carpio

Authors: Shahid Mahboob, Hafiz Muhammad Ashraf, Salma Sultana, Tayyaba Sultana, Khalid Al-Ghanim, Fahid Al-Misned, Zubair Ahmedd

Abstract:

There is an increasing need for an effective tool to estimate the risks derived from the large number of pollutants released to the environment by human activities. Typical screening procedures are highly invasive or lethal to the fish. Recent studies show that fish scales biochemically respond to a range of contaminants, including toxic metals, organic compounds, and endocrine disruptors. The present study evaluated the effects of the surface water contaminants on Cyprinus carpio in the Ravi River by comparing DNA extracted non-lethally from their scales to DNA extracted from the scales of fish collected from a controlled fish farm. A single, random sampling was conducted. Fish were broadly categorised into three weight categories (W1, W2 and W3). The experimental samples in the W1, W2 and W3 categories had an average DNA concentration (µg/µl) that was lower than the control samples. All control samples had a single DNA band; whereas the experimental samples in W1 fish had 1 to 2 bands, the experimental samples in W2 fish had two bands and the experimental samples in W3 fish had fragmentation in the form of three bands. These bands exhibit the effects of pollution on fish in the Ravi River. On the basis findings of this study, we propose that fish scales can be successfully employed as a new non-lethal tool for the evaluation of the effect of surface water contaminants.

Keywords: fish scales, Cyprinus carpio, heavy metals, non-invasive, DNA fragmentation

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1430 Temporal Effects on Chemical Composition of Treated Wastewater and Borehole Water Used for Irrigation in Limpopo Province, South Africa

Authors: Pholosho M. Kgopa, Phatu W. Mashela, Alen Manyevere

Abstract:

Increasing incidents of drought spells in most Sub-Saharan Africa call for using alternative sources of water for irrigation in arid and semi-arid regions. A study was conducted to investigate chemical composition of borehole and treated wastewater from different sampling disposal sites at University of Limpopo Experimental Farm (ULEF). A 4 × 5 factorial experiment, with the borehole as a reference sampling site and three other sampling sites along the wastewater disposal system was conducted over five months. Water samples were collected at four sites namely, (a) exit from Pond 16 into the furrow, (b) entry into night-dam, (c) exit from night dam to irrigated fields and (d) exit from borehole to irrigated fields. Water samples were collected in the middle of each month, starting from July to November 2016. Samples were analysed for pH, EC, Ca, Mg, Na, K, Al, B, Zn, Cu, Cr, Pb, Cd and As. The site × time interactions were highly significant for Ca, Mg, Zn, Cu, Cr, Pb, Cd, and As variables, but not for Na and K. Sampling site was highly significant on all variables, with sampling period not significant for K and Na. Relative to water from the borehole, Na concentration in wastewater samples from the night-dam exit, night-dam entry and Pond16 exit were lower by 69, 34 and 55%, respectively. Relative to borehole water, Al was higher in wastewater sampling sites. In conclusion, both sampling site and period affected the chemical composition of treated wastewater.

Keywords: irrigation water quality, spatial effects, temporal effects, water reuse, water scarcity

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1429 Influence of Boron and Germanium Doping on Physical-Mechanical Properties of Monocrystalline Silicon

Authors: Ia Kurashvili, Giorgi Darsavelidze, Giorgi Chubinidze, Marina Kadaria

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Boron-doped Czochralski (CZ) silicon of p-type, widely used in the photovoltaic industry is suffering from the light-induced-degradation (LID) of bulk electrophysical characteristics. This is caused by specific metastable B-O defects, which are characterized by strong recombination activity. In this regard, it is actual to suppress B-O defects in CZ silicon. One of the methods is doping of silicon by different isovalent elements (Ge, C, Sn). The present work deals with the investigations of the influence of germanium doping on the internal friction and shear modulus amplitude dependences in the temperature interval of 600-800⁰C and 0.5-5 Hz frequency range in boron-containing monocrystalline silicon. Experimental specimens were grown by Czochralski method (CZ) in [111] direction. Four different specimens were investigated: Si+0,5at%Ge:B (5.1015cm-3), Si+0,5at%Ge:B (1.1019cm-3), Si+2at%Ge:B (5.1015cm-3) and Si+2at%Ge:B (1.1019cm-3). Increasing tendency of dislocation density and inhomogeneous distribution in silicon crystals with high content of boron and germanium were revealed by metallographic studies on the optical microscope of NMM-80RF/TRF. Weak increase of current carriers-holes concentration and slight decrease of their mobility were observed by Van der Pauw method on Ecopia HMS-3000 device. Non-monotonous changes of dislocation origin defects mobility and microplastic deformation characteristics influenced by measuring temperatures and boron and germanium concentrations were revealed. Possible mechanisms of changes of mechanical characteristics in Si-Ge experimental specimens were discussed.

Keywords: dislocation, internal friction, microplastic deformation, shear modulus

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1428 Analysis of Veterinary Drug Residues and Pesticide Residues in Beehive Products

Authors: Alba Luna Jimenez, Maria Dolores Hernando

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The administration of veterinary treatments at higher doses than the recommended Varroa mite control in beehive matrices has the potential to generate residues in the honeybee colony and in the derived products for consumption. Honeybee colonies can also be indirectly exposed to residues of plant protection products when foraging in crops, wildflowers near the crops, or in urban gardens just after spraying. The study evaluates the presence of both types of residues, veterinary treatments, and pesticides in beeswax, bee bread, and honey. The study was carried out in apiaries located in agricultural zones and forest areas in Andalusia, Spain. Up to nineteen residues were identified above LOQ using gas chromatography-triple quadrupole-mass spectrometry analysis (GC-MS/MS). Samples were extracted by a modified QuEChERs method. Chlorfenvinphos was detected in beeswax and bee bread despite its use is not authorized for Varroa mite control. Residues of fluvalinate-tau, authorized as veterinary treatment, were detected in most of the samples of beeswax and bee bread, presumably due to overdose or also to its potential for accumulation associated with its marked liposolubility. Residues of plant protection products were also detected in samples of beeswax and bee bread. Pesticide residues were detected above the LOQ that was established at 5 µg.kg⁻¹, which is the minimum concentration that can be quantified with acceptable accuracy and precision, as described in the European guidelines for pesticide residue analysis SANTE/11945/2015. No residues of phytosanitary treatments used in agriculture were detected in honey.

Keywords: honeybee colony, mass spectrometry analysis, pesticide residues, Varroa destructor, veterinary treatment

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1427 Effect of Scrotal Circumference on Freezability of Bangladeshi Crossbred Bulls

Authors: Ajeet K. Jha, Pankaj K. Jha, Pravin Mishra

Abstract:

The study was conducted to evaluate the freezability of crossbred bulls’ semen at early age. Semen of three consecutive collections at 7 days interval from 12 crossbred bulls 17 was evaluated. The age at first collection was 15 to 20 months. Evaluation of semen was done soon after collection. Triladyl, Minitub, Germany was used as extender and was frozen using standard semen freezing protocol. Post-thaw sperm motility was evaluated. Morphology of paraformaldehyde fixed spermatozoa was evaluated under differential interference phase contrast microscopy and the viability of spermatozoa was evaluated by using stain SYBR-14 (1 mM/ml) and propidium iodide (2.41 mM/ml) under an epifluorescent microscopy. Scrotal circumference was correlated with all possible measures in all groups of crossbred bulls. Volume of semen, sperm concentration, total number of spermatozoa, initial sperm motility, post-thaw sperm motility, proportion of normal spermatozoa and proportion of live spermatozoa were compared among individual bull within and between two groups of crossbred bulls. A significant positive correlation was observed between scrotal circumference and volume of semen and between scrotal circumference and the total number of sperm production per ejaculate (r = 0.72, p < 0.04). Significant variation was observed in different semen parameters among individual bulls within the same group (p < 0.05) but no significant variation was found between two groups of crossbred bulls. Out of 12 bulls, semen freezability of 10 bulls was found satisfactory while semen of 2 bulls (Local × Friesian) was unsatisfactory. In conclusion, crossbred bulls aged 18 months having scrotal circumference > 30 cm produce freezable quality semen.

Keywords: Bangladesh, crossbred bull, scrotal circumference, semen freezability

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1426 Physicochemical and Sensorial Evaluation of Astringency Reduction in Cashew Apple (Annacardium occidentale L.) Powder Processing in Cookie Elaboration

Authors: Elida Gastelum-Martinez, Neith A. Pacheco-Lopez, Juan L. Morales-Landa

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Cashew agroindustry obtained from cashew apple crop (Anacardium occidentale L.) generates large amounts of unused waste in Campeche, Mexico. Despite having a high content of nutritional compounds such as ascorbic acid, carotenoids, fiber, carbohydrates, and minerals, it is not consumed due to its astringent sensation. The aim of this work was to develop a processing method for cashew apple waste in order to obtain a powder with reduced astringency able to be used as an additive in the food industry. The processing method consisted first in reducing astringency by inducing tannins from cashew apple peel to react and form precipitating complexes with a colloid rich in proline and histidine. Then cashew apples were processed to obtain a dry powder. Astringency reduction was determined by total phenolic content and evaluated by sensorial analysis in cashew-apple-powder based cookies. Total phenolic content in processed powders showed up to 72% lower concentration compared to control samples. The sensorial evaluation indicated that cookies baked using cashew apple powder with reduced astringency were 96.8% preferred. Sensorial characteristics like texture, color and taste were also well-accepted attributes. In conclusion, the method applied for astringency reduction is a viable tool to produce cashew apple powder with desirable sensorial properties to be used in the development of food products.

Keywords: astringency reduction, cashew apple waste, food industry, sensorial evaluation

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1425 An Investigation of Surface Texturing by Ultrasonic Impingement of Micro-Particles

Authors: Nagalingam Arun Prasanth, Ahmed Syed Adnan, S. H. Yeo

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Surface topography plays a significant role in the functional performance of engineered parts. It is important to have a control on the surface geometry and understanding on the surface details to get the desired performance. Hence, in the current research contribution, a non-contact micro-texturing technique has been explored and developed. The technique involves ultrasonic excitation of a tool as a prime source of surface texturing for aluminum alloy workpieces. The specimen surface is polished first and is then immersed in a liquid bath containing 10% weight concentration of Ti6Al4V grade 5 spherical powders. A submerged slurry jet is used to recirculate the spherical powders under the ultrasonic horn which is excited at an ultrasonic frequency and amplitude of 40 kHz and 70 µm respectively. The distance between the horn and workpiece surface was remained fixed at 200 µm using a precision control stage. Texturing effects were investigated for different process timings of 1, 3 and 5 s. Thereafter, the specimens were cleaned in an ultrasonic bath for 5 mins to remove loose debris on the surface. The developed surfaces are characterized by optical and contact surface profiler. The optical microscopic images show a texture of circular spots on the workpiece surface indented by titanium spherical balls. Waviness patterns obtained from contact surface profiler supports the texturing effect produced from the proposed technique. Furthermore, water droplet tests were performed to show the efficacy of the proposed technique to develop hydrophilic surfaces and to quantify the texturing effect produced.

Keywords: surface texturing, surface modification, topography, ultrasonic

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1424 Effect of Endurance Training on Serum Chemerin Levels and Lipid Profile of Plasma in Obese Women

Authors: A. Moghadasein, M. Ghasemi, S. Fazelifar

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Aim: Chemerin is a novel adipokine that play an important role in regulating lipid metabolism and abiogenesis. Chemerin is dependent on autocrine and paracrine signals for the differentiation and maturation of fat cells; it also regulates glucose uptake in fat cells and stimulates lipolysis. It has been reported that in adipocytes, chemerin enhances the insulin-stimulated glucose and causes the phosphorylation of tyrosine in Insulin receptor substrate. According to the studies, Chemerin may increase insulin sensitivity in adipose tissue and is largely associated with Body mass index, triglycerides, and blood pressure in those with normal glucose tolerance. There is limited information available regarding the effect of exercise training on serum chemerin concentrations. The purpose of this study was to investigate the effect of endurance training on serum chemerin levels and lipids of plasma in overweight women. Methodology: This study was a quasi-experimental research with a pre-post test design. After required examination and verification of high pressure by the physician, 22 obese subjects (age: 35.64±5.55 yr, weight: 75.62±9.30 kg, body mass index: 32.4±1.6 kg/m2) were randomly assigned to aerobic training (n= 12) and control (n= 12) groups. Participants completed a questionnaire indicating the lack of sports history during the past six months, the lack of anti-hypertension drugs use, hormone therapy, cardiovascular problems, and complete stoppage of menstrual cycle. Aerobic training was performed 3 times weekly for 8 weeks. Resting levels of chemerin plasma, metabolic parameters were measured prior to and after the intervention. The control group did not participate in any training program. In this study, ethical considerations included the complete description of the objectives to the study participants, ensuring the confidentiality of their information. Kolmogorov-Smirnov and Levin test were used for determining the normal distribution of data and homogeneity of variances, respectively. Analyze of variance with repeated measure were used to investigate the changes in the intra-group and the differences in inter-group of variables. Statistical operations were performed using SPSS 16 and the significance level of the tests was considered at P < 0.05. Results: After an 8 week aerobic training, levels of chemerin plasma were significantly decreased in aerobic trained group when compared with their control groups (p < 0.05).Concurrently, levels of HDL-c were significantly decreased (p < 0.05) whereas, levels of cholesterol, TG and LDL-c, showed no significant changes (p > 0.05). No significant correlations between chemerin levels and weight loss were observed in subjects with overweight women. Conclusion: The present study demonstrated, 8 weeks aerobic training, reduced serum chemerin concentrations in overweight women. Whereas, aerobic training exercise programmers affected the lipid profile response of obese subjects differently. However further research is warranted in order to unravel the molecular mechanism for the range of responses and the role of serum chemerin.

Keywords: chemerin, aerobic training, lipid profile, obese women

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1423 Effect of Silicon on Tritrophic Interaction of Cotton, Whitefly and Chrysoperla carnea

Authors: Asim Abbasi, Muhammad Sufyan

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The present experiment was carried out to examine the effects of silicon dioxide on tritrophic interaction of cotton, whitefly, and the predator Chrysoperla carnea. Population of whitefly was maintained on silicon treated and non-treated cotton for two generations in greenhouse net cages exposed to outside temperature and luminosity. The cotton was treated with silicon dioxide twice after 15 days intervals with 200 ppm concentration. A stock rearing of the natural predator was developed in the laboratory conditions. In the bioassay eggs of the predator all at the same age were individualized in glass petri plates that will be pierced with a pin to allow aeration and maintained in an incubator at 28 ± 2°C, 70 ± 10% relative humidity and 12h photo phase. Population of whitefly stayed on silicon treated, and non-treated cotton were offered to newly hatched chrysopid larvae until the end of the larval stage, assuring a permanent supply. Feeding preference of C. carnea along with longevity, survival of each instar larvae, pupation, adult emergence, and fecundity was checked. The results revealed that there was no significant difference in the feeding preference of C. carnea among both treatments. Durations of 1st and 2nd larval instar were also at par in both treatments. However overall longevity and adult emergence were a bit lower in silicon treated whitefly treatment. This may be due to the fact that silicon reduces the nutritional quality of host because of reduced whitefly feeding on silicon treated cotton. No significant difference in 1st and 2nd larval instars and then increased larval duration in later instars suggested that the effect of silicon treated host should be checked on more than 1 generation of C. carnea to get better findings.

Keywords: Chrysoperla carnea, silicon, tritrophic, whitefly

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1422 Study of Contrast Induced Nephropathy in Patients Undergoing Cardiac Catheterization: Upper Egypt Experience

Authors: Ali Kassem, Sharf Eldeen-Shazly, Alshemaa Lotfy

Abstract:

Introduction: Contrast-induced nephropathy (CIN) has been the third leading cause of hospital-acquired renal failure. Patients with cardiac diseases are particularly at risk especially with repeated injections of contrast media. CIN is generally defined as an increase in serum creatinine concentration of > 0.5 mg/dL or 25% above baseline within 48 hours after contrast administration. Aim of work: To examine the frequency of CIN for patients undergoing cardiac catheterization at Sohag University Hospital (Upper Egypt) and to identify possible risk factors for CIN in these patients. Material and methods: The study included 104 patients with mean age 56.11 ±10.03, 64(61.5%) are males while 40(38.5%) are females. 44(42.3%) patients are diabetics, 43(41%) patients are hypertensive, 6(5.7%) patients have congestive heart failure, 69(66.3%) patients on statins, 74 (71.2 %) are on ACEIs or ARBs, 19(15.4%) are on metformin, 6 (5.8%) are on NSAIDs, 30(28.8%) are on diuretics. RESULTS: Patients were classified at the end of the study into two groups: Group A: Included 91 patients who did not develop CIN. Group B: Included 13 patients who developed CIN, of which serum creatinine raised > 0.5mg/dl in 6 patients and raised > 25% from the baseline after the procedure in 13 patients. The overall incidence of CIN was 12.5%. CIN increased with older age. There was an increase in the incidence of CIN in diabetic versus non-diabetic patients (20.5% and 6.7%) respectively. (p< 0.03). There was a highly significant increase in the incidence of CIN in patients with CHF versus those without CHF (100% and 71%) respectively, (P<0001). Patients on diuretics showed a significant increase in the incidence of CIN representing 61.5% of all patients who developed CIN. Conclusion: Older patients, diabetic patients, patients with CHF and patients on diuretics have higher risk of developing CIN during coronary catheterization and should receive reno-protective measures before contrast exposure.

Keywords: cardiac diseases, contrast-induced nephropathy, coronary catheterization, CIN

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1421 A Comparison of Generation Dependent Brain Targeting Potential of(Poly Propylene Mine) Dendrimers

Authors: Nitin Dwivedi, Jigna Shah

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Aim and objective of study: This article indicates a comparison among various generations of dendrimers, a dendrimer is a bioactive material has repetitively branched molecule and used for delivery of various therapeutic active agents. This debut report compares the effect various generations of PPI dendrimers for brain targeting and management of neurodegenerative disorders potential on single platform. This report involves the study of the various mechanism of synthesis ligand anchored various generations PPI dendrimers deliver the drug directly to the CNS, prove their effectiveness in the management of the various neurodegenerative disease. Material and Methods: The Memantine an anti-Alzheimer drug loaded in different generations (3.0G, 4.0G, and 5.0G) of PPI dendrimers which were synthesized were synthesized. The various studies investigate the effect of PPI dendrimers generation on different characteristic parameters i.e. synthesis procedure, drug loading, release behavior, hemolysis profile at different concentration, MRI study for determine the route drug from olfactory transfer, animal model study in vitro, as well as in vivo performance. The outcomes of the investigation indicate drug delivery benefit as well as superior biocompatibility of 4.0G PPI dendrimer over 3.0G and 5.0G dendrimer, respectively. Results and Conclusion: The above study indicate the superiority of in drug delivery system with maximum drug utilization and minimize the drug dose for neurodegenerative disorder over 5.0G PPI dendrimers. So, 4.0G PPI dendrimers are the safe formulations for the symptomatic treatment of the neurodegenerative disorder. The fifth-generation poly(propyleneimine) (PPI) dendrimers, inherent toxicity due to the presence of many peripheral cationic groups is the major issue that limits their applicability.

Keywords: Alzheimer disease, generation, memantine, PPI

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1420 Enzymatic Determination of Limonene in Red Clover Genotypes

Authors: Andrés Quiroz, Emilio Hormazabal, Ana Mutis, Fernando Ortega, Manuel Chacón-Fuentes, Leonardo Parra

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Red clover (Trifolium pratense L.) is an important forage species in temperate regions of the world. The main limitation of this species worldwide is a lack of persistence related to the high mortality of plants due to a complex of biotic and abiotic factors, determining a life span of two or three seasons. Because of the importance of red clover in Chile, a red clover breeding program was started at INIA Carillanca Research Center in 1989, with the main objective of improving the survival of plants, forage yield, and persistence. The main selection criteria for selecting new varieties have been based on agronomical parameters and biotic factors. The main biotic factor associated with red clover mortality in Chile is Hylastinus obscurus (Coleoptera: Curculionidae). Both larval and adults feed on the roots, causing weakening and subsequent death of clover plants. Pesticides have not been successful for controlling infestations of this root borer. Therefore, alternative strategies for controlling this pest are a high priority for red clover producers. Currently, the role of semiochemical in the interaction between H. obscurus and red clover plants has been widely studied for our group. Specifically, from the red clover foliage has been identified limonene is eliciting repellency from the root borer. Limonene is generated in the plant from two independent biosynthetic pathways, the mevalonic acid, and deoxyxylulose pathway. Mevalonate pathway enzymes are localized in the cytosol, whereas the deoxyxylulose phosphate pathway enzymes are found in plastids. In summary, limonene can be determinated by enzymatic bioassay using GPP as substrate and by limonene synthase expression. Therefore, the main objective of this work was to study genetic variation of limonene in material provided by INIA´s Red Clover breeding program. Protein extraction was carried out homogenizing 250 mg of leave tissue and suspended in 6 mL of extraction buffer (PEG 1500, PVP-30, 20 mM MgCl2 and antioxidants) and stirred on ice for 20 min. After centrifugation, aliquots of 2.5 mL were desalted on PD-10 columns, resulting in a final volume of 3.5 mL. Protein determination was performed according to Bradford with BSA as a standard. Monoterpene synthase assays were performed with 50 µL of protein extracts transferred into gas-tight 2 mL crimp seal vials after addition of 4 µL MgCl₂ and 41 µL assay buffer. The assay was started by adding 5 µL of a GPP solution. The mixture was incubated for 30 min at 40 °C. Biosynthesized limonene was quantified in a GC equipped with a chiral column and using synthetic R and S-limonene standards. The enzymatic the production of R and S-limonene from different Superqueli-Carillanca genotypes is shown in this work. Preliminary results showed significant differences in limonene content among the genotypes analyzed. These results constitute an important base for selecting genotypes with a high content of this repellent monoterpene towards H. obscurus.

Keywords: head space, limonene enzymatic determination, red clover, Hylastinus obscurus

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1419 Stability-Indicating High-Performance Thin-Layer Chromatography Method for Estimation of Naftopidil

Authors: P. S. Jain, K. D. Bobade, S. J. Surana

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A simple, selective, precise and Stability-indicating High-performance thin-layer chromatographic method for analysis of Naftopidil both in a bulk and in pharmaceutical formulation has been developed and validated. The method employed, HPTLC aluminium plates precoated with silica gel as the stationary phase. The solvent system consisted of hexane: ethyl acetate: glacial acetic acid (4:4:2 v/v). The system was found to give compact spot for Naftopidil (Rf value of 0.43±0.02). Densitometric analysis of Naftopidil was carried out in the absorbance mode at 253 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r2=0.999±0.0001 with respect to peak area in the concentration range 200-1200 ng per spot. The method was validated for precision, recovery and robustness. The limits of detection and quantification were 20.35 and 61.68 ng per spot, respectively. Naftopidil was subjected to acid and alkali hydrolysis, oxidation and thermal degradation. The drug undergoes degradation under acidic, basic, oxidation and thermal conditions. This indicates that the drug is susceptible to acid, base, oxidation and thermal conditions. The degraded product was well resolved from the pure drug with significantly different Rf value. Statistical analysis proves that the method is repeatable, selective and accurate for the estimation of investigated drug. The proposed developed HPTLC method can be applied for identification and quantitative determination of Naftopidil in bulk drug and pharmaceutical formulation.

Keywords: naftopidil, HPTLC, validation, stability, degradation

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1418 Factors Influencing Bank Profitability of Czech Banks and Their International Parent Companies

Authors: Libena Cernohorska

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The goal of this paper is to specify factors influencing the profitability of selected banks. Next, a model will be created to help establish variables that have a demonstrable influence on the development of the selected banks' profitability ratios. Czech banks and their international parent companies were selected for analyzing profitability. Banks categorized as large banks (according to the Czech National Bank's system, which ranks banks according to balance sheet total) were selected to represent the Czech banks. Two ratios, the return on assets ratio (ROA) and the return on equity ratio (ROE) are used to assess bank profitability. Six endogenous and four external indicators were selected from among other factors that influence bank profitability. The data analyzed were for the years 2001 – 2013. First, correlation analysis, which was supposed to eliminate correlated values, was conducted. A large number of correlated values were established on the basis of this analysis. The strongly correlated values were omitted. Despite this, the subsequent regression analysis of profitability for the individual banks that were selected did not confirm that the selected variables influenced their profitability. The studied factors' influence on bank profitability was demonstrated only for Československá Obchodní Banka and Société Générale using regression analysis. For Československá Obchodní Banka, it was demonstrated that inflation level and the amount of the central bank's interest rate influenced the return on assets ratio and that capital adequacy and market concentration influenced the return on equity ratio for Société Générale.

Keywords: banks, profitability, regression analysis, ROA, ROE

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1417 Exploring Bio-Inspired Catecholamine Chemistry to Design Durable Anti-Fungal Wound Dressings

Authors: Chetna Dhand, Venkatesh Mayandi, Silvia Marrero Diaz, Roger W. Beuerman, Seeram Ramakrishna, Rajamani Lakshminarayanan

Abstract:

Sturdy Insect Cuticle Sclerotization, Incredible Substrate independent Mussel’s bioadhesion, Tanning of Leather are some of catechol(amine)s mediated natural processes. Chemical contemplation spots toward a mechanism instigated with the formation of the quinone moieties from the respective catechol(amine)s, via oxidation, followed by the nucleophilic addition of the amino acids/proteins/peptides to this quinone leads to the development of highly strong, cross-linked and water-resistant proteinacious structures. Inspired with this remarkable catechol(amine)s chemistry towards amino acids/proteins/peptides, we attempted to design highly stable and water-resistant antifungal wound dressing mats with exceptional durability using collagen (protein), dopamine (catecholamine) and antifungal drugs (Amphotericin B and Caspofungin) as the key materials. Electrospinning technique has been used to fabricate desired nanofibrous mat including Collagen (COLL), COLL/Dopamine (COLL/DP) and calcium incorporated COLL/DP (COLL-DP-Ca2+). The prepared protein-based scaffolds have been studied for their microscopic investigations (SEM, TEM, and AFM), structural analysis (FT-IR), mechanical properties, water wettability characteristics and aqueous stability. Biocompatibility of these scaffolds has been analyzed for dermal fibroblast cells using MTS assay, Cell TrackerTM Green CMFDA and confocal imaging. Being the winner sample, COLL-DP-Ca2+ scaffold has been selected for incorporating two antifungal drugs namely Caspofungin (Peptide based) and Amphotericin B (Non-Peptide based). Antifungal efficiency of the designed mats has been evaluated for eight diverse fungal strains employing different microbial assays including disc diffusion, cell-viability assay, time kill kinetics etc. To confirm the durability of these mats, in term of their antifungal activity, drug leaching studies has been performed and monitored using disc diffusion assay each day. Ex-vivo fungal infection model has also been developed and utilized to validate the antifungal efficacy of the designed wound dressings. Results clearly reveal dopamine mediated crosslinking within COLL-antifungal scaffolds that leads to the generation of highly stable, mechanical tough, biocompatible wound dressings having the zone of inhabitation of ≥ 2 cm for almost all the investigated fungal strains. Leaching studies and Ex-vivo model has confirmed the durability of these wound dressing for more than 3 weeks and certified their suitability for commercialization. A model has also been proposed to enlighten the chemical mechanism involved for the development of these antifungal wound dressings with exceptional robustness.

Keywords: catecholamine chemistry, electrospinning technique, antifungals, wound dressings, collagen

Procedia PDF Downloads 341
1416 Evaluation of the Antibacterial Activity of New Dermaseptin Derivatives Against Acinetobacter Baumannii

Authors: Houda Haddad, Radhia Mejri, , Alyne Rodrigues de Araujo, Amira Zairi

Abstract:

Nosocomial infections represent one of the biggest health problems nowadays. Acinetobacter baumannii is known as an opportunistic pathogen in humans, affecting people with compromised immune systems, and is becoming increasingly important as a hospital-derived infection. It is known that in recent years, more and more bacteria have become multidrug-resistant (MDR), and for this reason, the development of new drugs is a priority. However, these products must not affect the human body, and therefore, cytotoxicity studies are mandatory. In this context, antimicrobial peptides with potential antibacterial proprieties could be an alternative. In this research, we describe the synthesis and the bioactivity of dermaseptins and their derivatives against Acinetobacter baumannii. The cytotoxicity of these dermaseptins was investigated on the HEp-2 cell line by the MTT cell viability assay. Thereafter, we studied morphological alterations caused by the action of one of the active peptides on the bacterial membrane using atomic force microscopy (AFM). The cytotoxicity of dermaseptins was concentration-dependent at microgram concentrations. It was observed that all tested analogs exhibit antibacterial activity with Minimum Inhibitory Concentrations (MICs) ranging from 3.125 to 12.5 μg/mL and Minimum Bactericidal Concentrations (MBCs) ranging from 6.25 to 25 μg/mL. Microscopic images obtained by AFM revealed morphological changes on the surface of treated bacteria caused by K4S4(1-16), as well as significant surface alterations. Overall, these findings demonstrate that dermaseptins might constitute new lead structures for the development of potent antibacterial agents against Acinetobacter baumannii infections.

Keywords: dermaseptin B2, dermaseptin S4, analogs, Acinetobacter baumannii, healthcare-associated infections, antibacterial activity

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1415 Identification of Phenolic Compounds with Antibacterial Activity in Raisin Extract

Authors: Yousef M. Abouzeed A. Elfahem, F. Zgheel, M. A. Saad, Mohamed O. Ahmed

Abstract:

The bioactive properties of phytochemicals indicate their potential as natural drug products to prevent and treat human disease; in particular, compounds with antioxidant and antimicrobial activities may represent a novel class of safe and effective drugs. Following desiccation, grapes (Vitis vinifera) become more resistant to microbial-based degradation, suggesting that raisins may be a source of antimicrobial compounds. To investigate this hypothesis, total phenolic extracts were obtained from common raisins, local market-sourced. The acetone extract was tested for antibacterial activity against four prevalent bacterial pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella spp. and Escherichia coli). Antibiotic sensitivity and the Minimum Inhibitory Concentration (MIC) were determined for each bacterium. High performance liquid chromatography was used to identify compounds in the total phenolic extract. The raisin phenolic extract inhibited growth of all the tested bacteria; the greatest inhibitive effect (normalized to cefotaxime sodium control antibiotic) occurred against P. aeruginosa, followed by S. aureus > Salmonella spp.= E. coli. The phenolic extracts contained the bioactive compounds catechin, quercetin, and rutin. Thus, phytochemicals in raisin extract have antibacterial properties; this plant-based extract, or its bioactive constituents, may represent a promising natural preservative or antimicrobial agent for the food industry or anti-infective drug.

Keywords: Vitis vinifera raisin, extraction, phenolic compounds, antibacterial activity

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1414 Evaluation of Toxic Metals in Water Hyacinth (Eichhornia crassipes) from Valsequillo Reservoir, Puebla, Central Mexico

Authors: Jacobo Tabla, P. F. Rodriguez-Espinosa, M. E. Perez-Lopez

Abstract:

Valsequillo reservoir located in Puebla City, Central Mexico receives water from the Atoyac River (Northwest) and from Alseseca River in the north. It has been the receptacle of municipal and industrial wastes for the past few decades affecting the water quality lethally. As a result, there is an outburst of water hyacinths (Eichhornia crassipes) in the reservoir occupying around 50 % of the total area. Therefore, the aim of the present work was to assess the concentration levels of toxic metals (Co, Zn, Ni, Cu and As) in the water hyacinths and the ambient waters during the dry season. Fourteen water samples and three water hyacinth samples were procured from the Valsequillo reservoir. The collected samples of water hyacinth (roots, rhizome, stems and leaves) were analyzed using an Inductively coupled plasma mass spectrometry (ICP-MS) Ultramass 700 (Varian Inc.) to determine the metal levels. Results showed that water hyacinth presented an exhaustion in metal capture from the inlet to outlet of the reservoir. The maximum bioaccumulation factors (BF) of Co, Zn, Ni, Cu and As were 5000, 47474, 4929, 17090 and 74000 respectively. On the other hand, the maximum Translocation Factor (TF) of 0.85 was observed in Zn, whilst Co presented the minimum TF of 0.059. Thus, the results presented the fact that water hyacinth in Valsequillo reservoir proves to be an important environmental utility for efficiently accumulating and translocating heavy metals from the ambient waters to its organelles (stems and leaves).

Keywords: bioaccumulation factor, toxic metals, translocation factor, water hyacinth

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1413 Participation in IAEA Proficiency Test to Analyse Cobalt, Strontium and Caesium in Seawater Using Direct Counting and Radiochemical Techniques

Authors: S. Visetpotjanakit, C. Khrautongkieo

Abstract:

Radiation monitoring in the environment and foodstuffs is one of the main responsibilities of Office of Atoms for Peace (OAP) as the nuclear regulatory body of Thailand. The main goal of the OAP is to assure the safety of the Thai people and environment from any radiological incidents. Various radioanalytical methods have been developed to monitor radiation and radionuclides in the environmental and foodstuff samples. To validate our analytical performance, several proficiency test exercises from the International Atomic Energy Agency (IAEA) have been performed. Here, the results of a proficiency test exercise referred to as the Proficiency Test for Tritium, Cobalt, Strontium and Caesium Isotopes in Seawater 2017 (IAEA-RML-2017-01) are presented. All radionuclides excepting ³H were analysed using various radioanalytical methods, i.e. direct gamma-ray counting for determining ⁶⁰Co, ¹³⁴Cs and ¹³⁷Cs and developed radiochemical techniques for analysing ¹³⁴Cs, ¹³⁷Cs using AMP pre-concentration technique and 90Sr using di-(2-ethylhexyl) phosphoric acid (HDEHP) liquid extraction technique. The analysis results were submitted to IAEA. All results passed IAEA criteria, i.e. accuracy, precision and trueness and obtained ‘Accepted’ statuses. These confirm the data quality from the OAP environmental radiation laboratory to monitor radiation in the environment.

Keywords: international atomic energy agency, proficiency test, radiation monitoring, seawater

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1412 Effect of Thermal Energy on Inorganic Coagulation for the Treatment of Industrial Wastewater

Authors: Abhishek Singh, Rajlakshmi Barman, Tanmay Shah

Abstract:

Coagulation is considered to be one of the predominant water treatment processes which improve the cost effectiveness of wastewater. The sole purpose of this experiment on thermal coagulation is to increase the efficiency and the rate of reaction. The process uses renewable sources of energy which comprises of improved and minimized time method in order to eradicate the water scarcity of the regions which are on the brink of depletion. This paper includes the various effects of temperature on the standard coagulation treatment of wastewater and their effect on water quality. In addition, the coagulation is done with the mix of bottom/fly-ash that will act as an adsorbent and removes most of the minor and macro particles by means of adsorption which not only helps to reduce the environmental burden of fly ash but also enhance economic benefit. Also, the method of sand filtration is amalgamated in the process. The sand filter is an environmentally-friendly wastewater treatment method, which is relatively simple and inexpensive. The existing parameters were satisfied with the experimental results obtained in this study and were found satisfactory. The initial turbidity of the wastewater is 162 NTU. The initial temperature of the wastewater is 27 C. The temperature variation of the entire process is 50 C-80 C. The concentration of alum in wastewater is 60mg/L-320mg/L. The turbidity range is 8.31-28.1 NTU after treatment. pH variation is 7.73-8.29. The effective time taken is 10 minutes for thermal mixing and sedimentation. The results indicate that the presence of thermal energy affects the coagulation treatment process. The influence of thermal energy on turbidity is assessed along with renewable energy sources and increase of the rate of reaction of the treatment process.

Keywords: adsorbent, sand filter, temperature, thermal coagulation

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1411 Miracle Fruit Application in Sour Beverages: Effect of Different Concentrations on the Temporal Sensory Profile and Overall Linking

Authors: Jéssica F. Rodrigues, Amanda C. Andrade, Sabrina C. Bastos, Sandra B. Coelho, Ana Carla M. Pinheiro

Abstract:

Currently, there is a great demand for the use of natural sweeteners due to the harmful effects of the high sugar and artificial sweeteners consumption on the health. Miracle fruit, which is known for its unique ability to modify the sour taste in sweet taste, has been shown to be a good alternative sweetener. However, it has a high production cost, being important to optimize lower contents to be used. Thus, the aim of this study was to assess the effect of different miracle fruit contents on the temporal (Time-intensity - TI and Temporal Dominance of Sensations - TDS) sensory profile and overall linking of lemonade, to determine the better content to be used as a natural sweetener in sour beverages. TI and TDS results showed that the concentrations of 150 mg, 300 mg and 600 mg miracle fruit were effective in reducing the acidity and promoting the sweet perception in lemonade. Furthermore, the concentrations of 300 mg and 600 mg obtained similar profiles. Through the acceptance test, the concentration of 300 mg miracle fruit was shown to be an efficient substitute for sucrose and sucralose in lemonade, once they had similar hedonic values between ‘I liked it slightly’ and ‘I liked it moderately’. Therefore, 300mg miracle fruit consists in an adequate content to be used as a natural sweetener of lemonade. The results of this work will help the food industry on the efficient application of a new natural sweetener- the Miracle fruit extract in sour beverages, reducing costs and providing a product that meets the consumer desires.

Keywords: acceptance, natural sweetener, temporal dominance of sensations, time-intensity

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1410 The Utilization of Salicylic Acid of the Extract from Avocado Skin as an Inhibitor of Ethylene Production to Keep the Quality of Banana in Storage

Authors: Adira Nofeadri Ryofi, Alvin Andrianus, Anna Khairunnisa, Anugrah Cahyo Widodo, Arbhyando Tri Putrananda, Arsy Imanda N. Raswati, Gita Rahmaningsih, Ina Agustina

Abstract:

The consumption level of fresh bananas from 2005 until 2010, increased from 8.2 to 10 kg/capita/year. The commercial scale of banana generally harvested when it still green to make the banana avoid physical damage, chemical, and disease after harvest and ripe fruit. That first metabolism activity can be used as a synthesis reaction. Ripening fruit was influenced by ethylene hormone that synthesized in fruit which is experiencing ripe and including hormone in the ripening fruit process in klimaterik phase. This ethylene hormone is affected by the respiration level that would speed up the restructuring of carbohydrates inside the fruit, so the weighting of fruit will be decreased. Compared to other klimaterik fruit, banana is a fruit that has a medium ethylene production rate and the rate of respiration is low. The salicylic acid can regulate the result number of the growth process or the development of fruits and plants. Salicylic acid serves to hinder biosynthesis ethylene and delay senses. The research aims to understand the influence of salicylic acid concentration that derived from the waste of avocado skin in inhibition process to ethylene production that the maturation can be controlled, so it can keep the quality of banana for storage. It is also to increase the potential value of the waste of avocado skin that were still used in industrial cosmetics.

Keywords: ethylene hormone, extract avocado skin, inhibitor, salicylic acid

Procedia PDF Downloads 203
1409 Evaluation of the Effects of Some Medicinal Plants Extracts on Seed

Authors: Areej Ali Baeshen, Hanaa Kamal Galal, Batoul Mohamed Abdullatif

Abstract:

In the present study, the allelopathic effects of Eruca sativa, Mentha peprinta, and Coriandrum sativum aqueous extracts, prepared by 25 gm and 50 gm of fresh leaves dissolved in 100 ml of double distilled water in addition to the crude extract (100%). The final concentrations were 100 %, 50%, 25% and 0% as control. The extracts were tested for their allelopathic effects on seed germination and other growth parameters of Phaseolous vulgaris. Laboratory experiments were conducted in sterilizes Petri dishes with 5 and 10 day time interval for seed germination and 24 h, 48 h and 72 h for radicle length on an average of 25°C. The effects of different concentrations of aqueous extract were compared to distilled water (0%). 25% and 50% aqueous extracts of Eruca sativa and Coriandrum sativum caused a pronounced inhibitory effect on seed germination and the tested growth parameters of the receptor plant. The inhibitory effect was proportional to the concentration of the extract. Mentha peprinta extracts, on the other hand, caused an increase in germination percentage and other growth parameters in Phaseolous vulgaris. Hence, it could be concluded that the aqueous extracts of Eruca sativa and Coriandrum sativum might contain water-soluble allelochemicals, which could inhibit the seed germination and reduce radicle length of Phaseolous vulgaris. Mentha peprinta has beneficial allelopathic effects on the receptor plant.

Keywords: Phaseolus vulgaris, Eruca sativa, Mentha peperinta, Coriandrum sativum, medicinal plants, seed germination

Procedia PDF Downloads 365
1408 Effects of Plant Growth Promoting Microbes and Mycorrhizal Fungi on Wheat Growth in the Saline Soil

Authors: Ahmed Elgharably, Nivien Nafady

Abstract:

Arbuscular mycorrhizal fungi (AMF) and plant growth promoting microbes (PGPM) can promote plant growth under saline conditions. This study investigated how AMF and PGPM affected the growth and grain yield of wheat at different soil salinity levels (0, 75 and 150 mM NaCl). AMF colonization percentage, grain yield and dry weights and lengths of shoot and root, N, P K, Na, malondialdehyde, chlorophyll and proline contents and shoot relative permeability were determined. Salinity reduced NPK uptake and malondialdehyde and chlorophyll contents, and increased shoot Na concentration, relative permeability, and proline content, and thus declined plant growth. PGPM inoculation enhanced AMF colonization, P uptake, and K/Na ratio, but alone had no significant effect on plant growth and grain yield. AMF inoculation significantly enhanced NPK uptake, increased chlorophyll content and decreased shoot relative permeability, proline and Na contents, and thus promoted the plant growth. The inoculation of PGPM significantly enhanced the positive effects of AMF in controlling Na uptake and in increasing chlorophyll and NPK contents. Compared to AMF inoculation alone, dual inoculation with AMF and PGPM resulted in approximately 10, 25 and 25% higher grain yield at 0, 75 and 150 mM NaCl, respectively. The results provide that PGPM inoculation can maximize the effects of AMF inoculation in alleviating the deleterious effects of NaCl salts on wheat growth.

Keywords: mycorrhizal fungi, salinity, sodium, wheat

Procedia PDF Downloads 147
1407 Normalized Difference Vegetation Index and Normalize Difference Chlorophyll Changes with Different Irrigation Levels on Sillage Corn

Authors: Cenk Aksit, Suleyman Kodal, Yusuf Ersoy Yildirim

Abstract:

Normalized Difference Vegetation Index (NDVI) is a widely used index in the world that provides reference information, such as the health status of the plant, and the density of the vegetation in a certain area, by making use of the electromagnetic radiation reflected from the plant surface. On the other hand, the chlorophyll index provides reference information about the chlorophyll density in the plant by making use of electromagnetic reflections at certain wavelengths. Chlorophyll concentration is higher in healthy plants and decreases as plant health decreases. This study, it was aimed to determine the changes in Normalize Difference Vegetation Index (NDVI) and Normalize Difference Chlorophyll (NDCI) of silage corn irrigated with subsurface drip irrigation systems under different irrigation levels. In 5 days irrigation interval, the daily potential plant water consumption values were collected, and the calculated amount was applied to the full irrigation and 3 irrigation water levels as irrigation water. The changes in NDVI and NDCI of silage corn irrigated with subsurface drip irrigation systems under different irrigation levels were determined. NDVI values have changed according to the amount of irrigation water applied, and the highest NDVI value has been reached in the subject where the most water is applied. Likewise, it was observed that the chlorophyll value decreased in direct proportion to the amount of irrigation water as the plant approached the harvest.

Keywords: NDVI, NDCI, sub-surface drip irrigation, silage corn, deficit irrigation

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1406 Fungicidal Action of the Mycogenic Silver Nanoparticles Against Aspergillus niger Inciting Collar Rot Disease in Groundnut (Arachis hypogaea L.)

Authors: R. Sarada Jayalakshmi Devi B. Bhaskar, S. Khayum Ahammed, T. N. V. K. V. Prasad

Abstract:

Use of bioagents and biofungicides is safe to manage the plant diseases and to avoid human health hazards which improves food security. Myconanotechnology is the study of nanoparticles synthesis using fungi and their applications. The present work reports on preparation, characterization and antifungal activity of biogenic silver nanoparticles produced by the fungus Trichoderma sp. which was collected from groundnut rhizosphere. The culture filtrate of Trichoderma sp. was used for the reduction of silver ions (Ag+) in AgNO3 solution to the silver (Ag0) nanoparticles. The different ages (4 days, 6 days, 8 days, 12 days, and 15 days) of culture filtrates were screened for the synthesis of silver nanoparticles. Synthesized silver nanoparticles were characterized using UV-Vis spectrophotometer, particle size and zeta potential analyzer, Fourier Transform Infrared Spectrophotometer (FTIR) and Transmission Electron Microscopy. Among all the treatments the silver nitrate solution treated with six days aged culture filtrate of Trichoderma sp. showed the UV absorption peak at 440 nm with maximum intensity (0.59) after 24 hrs incubation. The TEM micrographs showed the spherical shaped silver nanoparticles with an average size of 30 nm. The antifungal activity of silver nanoparticles against Aspergillus niger causing collar rot disease in groundnut and aspergillosis in humans showed the highest per cent inhibition at 100 ppm concentration (74.8%). The results points to the usage of these mycogenic AgNPs in agriculture to control plant diseases.

Keywords: groundnut rhizosphere, Trichoderma sp., silver nanoparticles synthesis, antifungal activity

Procedia PDF Downloads 466
1405 Effect of Different Parameters on the Swelling Behaviour of Thermo-Responsive Elastomers in a Nematogenic Solvent

Authors: Nouria Bouchikhi, Soufiane Bedjaoui, C. Tewfik Bouchaour, Lamia Alachaher Bedjaoui, Ulrich Maschke

Abstract:

Swelling properties and phase diagrams of binary systems composed of liquid crystalline networks and a low molecular mass liquid crystal (LMWLC) have been investigated. The networks were prepared by ultraviolet (UV) irradiation of reactive mixtures including a monomer, a cross-linking agent and a photo-initiator. These networks were prepared using two cross-linking agents: 1,6 hexanedioldiacrylate (HDDA) and a mesogenic acrylic acid 6-(4’-(6-acryloyloxy-hexyloxy) biphenyl-4-yl oxy) hexyl ester (AHBH). The obtained dry networks were characterized by differential scanning calorimetry, and immersed in an excess of a LMWLC solvent 4-cyano-4’-pentylbiphenyl (5CB), forming polymer gels. A detailed study by polarized optical microscopy allowed to determine the swelling degree of the gels and to follow the phase behavior of the solvent inside the polymer matrix in a wide range of temperature. It has been found that the gels undergo a sharp decrease of their swelling degree in response to an infinitesimal change of temperature. This finding adds new and interesting aspects on the actuators applications. We have subsequently explored the effect of different parameters on volume phase transition of these liquid crystalline materials. Such as the cross-linking density (CD), a nature of cross-linking agent and the photo initiator concentration.

Keywords: cross-linking density, liquid crystalline elastomers, phase diagrams, swelling

Procedia PDF Downloads 294