Search results for: nitrogen levels
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 8093

Search results for: nitrogen levels

7553 Plant Growth, Symbiotic Performance and Grain Yield of 63 Common Bean Genotypes Grown Under Field Conditions at Malkerns Eswatini

Authors: Rotondwa P. Gunununu, Mustapha Mohammed, Felix D. Dakora

Abstract:

Common bean is the most importantly high protein grain legume grown in Southern Africa for human consumption and income generation. Although common bean can associate with rhizobia to fix N₂ for bacterial use and plant growth, it is reported to be a poor nitrogen fixer when compared to other legumes. N₂ fixation can vary with legume species, genotype and rhizobial strain. Therefore, screening legume germplasm can reveal rhizobia/genotype combinations with high N₂-fixing efficiency for use by farmers. This study assessed symbiotic performance and N₂ fixation in 63 common bean genotypes under field conditions at Malkerns Station in Eswatini, using the ¹⁵N natural abundance technique. The shoots of common bean genotypes were sampled at a pod-filling stage, oven-dried (65oC for 72h), weighed, ground into a fine powder (0.50 mm sieve), and subjected to ¹⁵N/¹⁴N isotopic analysis using mass spectrometry. At maturity, plants from the inner rows were harvested for the determination of grain yield. The results revealed significantly higher modulation (p≤0.05) in genotypes MCA98 and CIM-RM01-97-8 relative to the other genotypes. Shoot N concentration was highest in genotype MCA 98, followed by KAB 10 F2.8-84, with most genotypes showing shoot N concentrations below 2%. Percent N derived from atmospheric N₂ fixation (%Ndfa) differed markedly among genotypes, with CIM-RM01-92-3 and DAB 174, respectively, recording the highest values of 66.65% and 66.22 % N derived from fixation. There were also significant differences in grain yield, with CIM-RM02-79-1 producing the highest yield (3618.75 kg/ha). These results represent an important contribution in the profiling of symbiotic functioning of common bean germplasm for improved N₂ fixation.

Keywords: nitrogen fixation, %Ndfa, ¹⁵N natural abundance, grain yield

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7552 Studies on the Physico-Chemical Parameters of Jebba Lake, Niger State, Nigeria

Authors: M. B. Mshelia, J. K. Balogun, J. Auta, N. O. Bankole

Abstract:

Studies on some aspects of the physico-chemical parameters of Jebba Lake, Niger State, Nigeria was carried out from January to December, 2011. The aim was to investigate some of the physico-chemical parameters relevant to life and health of fish in the water body. Six (6) sampling sites were selected at random which covered Northern (Faku and Awuru), middle (Old Gbajibo and Shankade) and southern zones (New Gbajibo and Jebba dam} of Jebba Lake. Sampling was carried out for the period of 12 Months. The Physico-chemical parameters that were considered were water temperature, pH, dissolved oxygen, electrical conductivity, water transparency, phosphate and nitrate. They were all measured using standard methods. The results showed that water temperature values ranged between 26.06 ± 0.15a in Jebba lake site to 27.34 ± 0.12b in Shankade sampling site, depth varied from 8.08m to 31.64m, water current was between 20.10.62 cm/sec and 26.46 cm/sec, Secchi disc transparency ranged from0.46±0.01 m in New Gbajibo, while the highest mean value was 0.53 ± 0.04 m in Jebba dam., pH varied from 6.49 ± 0.01 and 7.59,5.35±0.03a mg/l in New Gbajibo and 6.75 ± 0.03 mg/l in Faku.The dissolved oxygen varied between 5.35±0.03a mg/l in New Gbajibo and 6.75 ± 0.03 mg/l in Faku.,The mean conductivity value was highest in Faku and Jebba with 128.8 ± 0.32 and 128.8 ± 0.42homs/cm) respectively, Alkalinity ranged 43.00±0.02 to33.30±0.32 mg/l., The nitrate-nitrogen range (2.37 ± 0.08 – 6.40 ± 0.50mg/l)., The mean values of phosphate-phosphorus (PO4-P) recorded varied between 0.18 ± 0.00 mg/l in Faku to 0.47 + 0.10 mg/l in Old Gbajibo.The highest mean value for total dissolved solids was 57.88 ± 0.28 mg/l in Shankade, while the lowest mean value of 39.17 ± 0.42 mg/l was recorded in Faku. Free CO2 ranged from 1.75 mg/l to 2.94 mg/l, Biochemical oxygen demand (BOD) was between 4.25 mg/l and 5.41 mg/l and nitrate-nitrogen concentration was between 2.37 mg/l and 6.40 mg/l. There were significant differences (P < 0.05) between these parameters in relation to stations. Generally, the physico-chemical characteristics of Lake Jebba were within the productive values for aquatic systems, and strongly indicate that the lake is unpolluted.

Keywords: Jebba Lake, water quality, secchi disc, DO meter, sampling sites, physico-chemical parameters

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7551 Interventions to Control Listeria Monocytogenes on Sliced Mushrooms

Authors: Alanna Goodman, Kayla Murray, Keith Warriner

Abstract:

The following reports on a comparative study on the efficacy of different decontamination technologies to decrease Listeria monocytogenes inoculated onto white sliced mushrooms and assesses the fate of residual levels during posttreatment storage under aerobic conditions at 8uC. The treatments were chemical (hydrogen peroxide, peroxyacetic acid, ozonated water, electrolyzed water, chitosan, lactic acid), biological (Listeria bacteriophages), and physical (UV-C, UV:hydrogen peroxide). None of the treatments achieved .1.2 log CFU reduction in L. monocytogenes levels; bacteriophages at a multiplicity of infection of 100 and 3% (vol/vol) hydrogen peroxide were the most effective of the treatments tested. However, growth of residual L. monocytogenes during posttreatment storage attained levels equal to or greater than levels in the nontreated controls. The growth of L. monocytogenes was inhibited on mushrooms treated with chitosan, electrolyzed water, peroxyacetic acid, or UV. Yet, L. monocytogenes inoculated onto mushrooms and treated with UV:hydrogen peroxide decreased during posttreatment storage, through a combination of sublethal injury and dehydration of the mushroom surface. Although mushrooms treated with UV:hydrogen peroxide became darker during storage, the samples were visually acceptable relative to controls. In conclusion, of the treatments evaluated, UV:hydrogen peroxide holds promise to control L. monocytogenes on mushroom surfaces.

Keywords: listeria monocytogenes, sliced mushrooms, bacteriophages, UV, sanitizers

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7550 Simultaneous Adsorption and Characterization of NOx and SOx Emissions from Power Generation Plant on Sliced Porous Activated Carbon Prepared by Physical Activation

Authors: Muhammad Shoaib, Hassan M. Al-Swaidan

Abstract:

Air pollution has been a major challenge for the scientists today, due to the release of toxic emissions from various industries like power plants, desalination plants, industrial processes and transportation vehicles. Harmful emissions into the air represent an environmental pressure that reflects negatively on human health and productivity, thus leading to a real loss in the national economy. Variety of air pollutants in the form of carbon oxides, hydrocarbons, nitrogen oxides, sulfur oxides, suspended particulate material etc. are present in air due to the combustion of different types of fuels like crude oil, diesel oil and natural gas. Among various pollutants, NOx and SOx emissions are considered as highly toxic due to its carcinogenicity and its relation with various health disorders. In Kingdom of Saudi Arabia electricity is generated by burning of crude, diesel or natural gas in the turbines of electricity stations. Out of these three, crude oil is used extensively for electricity generation. Due to the burning of the crude oil there are heavy contents of gaseous pollutants like sulfur dioxides (SOx) and nitrogen oxides (NOx), gases which are ultimately discharged in to the environment and is a serious environmental threat. The breakthrough point in case of lab studies using 1 gm of sliced activated carbon adsorbant comes after 20 and 30 minutes for NOx and SOx, respectively, whereas in case of PP8 plant breakthrough point comes in seconds. The saturation point in case of lab studies comes after 100 and 120 minutes and for actual PP8 plant it comes after 60 and 90 minutes for NOx and SOx adsorption, respectively. Surface characterization of NOx and SOx adsorption on SAC confirms the presence of peaks in the FT-IR spectrum. CHNS study verifies that the SAC is suitable for NOx and SOx along with some other C and H containing compounds coming out from stack emission stream from the turbines of a power plant.

Keywords: activated carbon, flue gases, NOx and SOx adsorption, physical activation, power plants

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7549 Studying the Evolution of Soot and Precursors in Turbulent Flames Using Laser Diagnostics

Authors: Muhammad A. Ashraf, Scott Steinmetz, Matthew J. Dunn, Assaad R. Masri

Abstract:

This study focuses on the evolution of soot and soot precursors in three different piloted diffusion turbulent flames. The fuel composition is as follow flame A (ethylene/nitrogen, 2:3 by volume), flame B (ethylene/air, 2:3 by volume), and flame C (pure methane). These flames are stabilized using a 4mm diameter jet surrounded by a pilot annulus with an outer diameter of 15 mm. The pilot issues combustion products from stoichiometric premixed flames of hydrogen, acetylene, and air. In all cases, the jet Reynolds number is 10,000, and air flows in the coflow stream at a velocity of 5 m/s. Time-resolved laser-induced fluorescence (LIF) is collected at two wavelength bands in the visible (445 nm) and UV regions (266 nm) along with laser-induced incandescence (LII). The combined results are employed to study concentration, size, and growth of soot and precursors. A set of four fast photo-multiplier tubes are used to record emission data in temporal domain. A 266nm laser pulse preferentially excites smaller nanoparticles which emit a fluorescence spectrum which is analysed to track the presence, evolution, and destruction of nanoparticles. A 1064nm laser pulse excites sufficiently large soot particles, and the resulting incandescence is collected at 1064nm. At downstream and outer radial locations, intermittency becomes a relevant factor. Therefore, data collected in turbulent flames is conditioned to account for intermittency so that the resulting mean profiles for scattering, fluorescence, and incandescence are shown for the events that contain traces of soot. It is found that in the upstream regions of the ethylene-air and ethylene-nitrogen flames, the presence of soot precursors is rather similar. However, further downstream, soot concentration grows larger in the ethylene-air flames.

Keywords: laser induced incandescence, laser induced fluorescence, soot, nanoparticles

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7548 The Effects of Six Weeks Endurance Training and Aloe Vera on COX-2 and VEGF Levels in Mice with Breast Cancer

Authors: Alireza Barari, Ahmad Abdi

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The aim of this study was to determine the effects of the effects of six weeks endurance training and Aloe Vera on cyclooxygenase 2 (COX-2) and VEGF levels in mice with breast cancer. For this purpose, 35 rats were randomly divided into 5 groups: control (healthy), control (cancer), training (cancer), Aloe Vera (cancer) and Aloe Vera + training (cancer). Induction of breast cancer tumors were done in mice by planting method. The training program includes six weeks of swimming training was done in three sessions per week. Training time from 10 minutes on the first day increased to 60 minutes in second week, and by stabilizing this time, the water flow rate was increased from 7 to 15 liters per minute. 300 mg per kg body weight of Aloe Vera extract was injected into the peritoneal. Sampling was done 48 hours after the last exercise session. K-S test to determine the normality of the data and analysis of variance for repeated measures and Tukey test was used to analyze the data. A significant difference in the p<0.05 accepted. The results showed that induction of cancer cells significantly increased levels of COX-2 in aloe group and VEGF in training and Aloe Vera + training groups. The results suggest that swimming exercise and Aloe Vera can reduce levels of COX-2 and VEGF in mice with breast cancer.The results of this study, Induction of cancer cells significantly increased levels of COX-2 and MMP-9 in the control group compared with the cancer control group. The results suggest that Aloe Vera can probably inhibit the cyclooxygenase pathway and thus production of prostaglandin E2 decrease of arachidonic acid.

Keywords: endurance training, aloe vera, COX-2, VEGF

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7547 The Need for the Inclusion of Museum Studies at All Levels of Education in Nigeria

Authors: Stephany Inalegwu

Abstract:

Museums play a very critical role in understanding the cultural values and the history of any given society in Nigeria and the world at large. The role of Museums as an avenue through which artefacts are collected, preserved and exhibited cannot be over emphasized as they are now seen as not only with the above stated aims but also as a creator of employment and revenue generation if properly harnessed. Interestingly, despite its importance, museum studies have been limited to University curriculum alone causing a dearth of information for the younger generation up until they attain the University age. It is against this background that this paper carefully analyses the definitions of museums, the state of museums and museum studies in Nigeria today and the need to include its studies at all the levels of Education in Nigeria from the primary, to secondary and tertiary levels. It should reflect a study of all ages, as this is vital in the development of individuals. It concludes by harping on the need for a better appreciation of the Nigerian culture ranging from the famous Nok Terracotta, Benin Bronze works etc and its importance of museums as an avenue to display the rich Nigerian cultural heritage.

Keywords: culture, curriculum, education, museum

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7546 Investigation of the Effect of Anaerobic Digestate on Antifungal Activity and in Different Parameters of Maize

Authors: Nazia Zaffar, Alam Khan, Abdul Haq, Malik Badshah

Abstract:

Pakistan is an agricultural country. The increasing population leads to an increase in demand for food. A large number of crops are infected by different microbes, and nutrient deficiency of soil adversely affects the yield of crops. Furthermore, the use of chemical fertilizers like Nitrogen, Phosphorus, Potassium (NPK) Urea, and Diammonium phosphate (DAP) and pesticides have environmental consequences. Therefore, there is an urgent need to explore alternative renewable and sustainable biofertilizers. Maize is one of the top growing crops in Pakistan, but it has low yield compared to other countries due to deficiency of organic matter, widespread nutrients deficiency (phosphorus and nitrogen), unbalanced use of fertilizers and various fungal diseases. In order to get rid of all these disadvantages, Digestate emerged as a win-win opportunity for the control of a few plant diseases and a replacement for the chemical fertilizers. The present study was designed to investigate the effect of Anerobic digestate on Antifungal Activity and in different parameters of Maize. The antifungal activity, minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC) against selected phytopathogens (Colletotrichum coccodis, Pythium ultimum, Phytophthora capsci, Rhizoctonia solani, Bipolaris oryzae and Fusarium Fujikuroi) were determined by microtiter plate method. The effect of various fertilizers in different growth parameters height, diameter, chlorophyll, leaf area, biomass, and yield were studied in field experiments. The extracts from anaerobic digestate have shown antifungal activity against selected phytopathogens, the highest activity was noted against P. ultimum, the MIC activity was high in case of P. ultimum and B. oryzae. The present study concludes that anaerobic digestate have a positive effect on maize growth and yield as well as an antifungal activity which can be potentially a good biofertilizer.

Keywords: anaerobic digestate, antifungal activity, MIC, phytopathogens

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7545 Diversification of Rice-Based Cropping Systems under Irrigated Condition

Authors: A. H. Nanher, N. P. Singh

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In India, Agriculture is largely in rice- based cropping system. It has indicated decline in factor productivity along with emergence of multi - nutrient deficiency, buildup of soil pathogen and weed flora because it operates and removes nutrients from the same rooting depth. In designing alternative cropping systems, the common approaches are crop intensification, crop diversification and cultivar options. The intensification leads to the diversification of the cropping system. Intensification is achieved by introducing an additional component crop in a pre-dominant sequential system by desirable adjustments in cultivars of one or all the component crops. Invariably, this results in higher land use efficiency and productivity per unit time Crop Diversification through such crop and inclusion of fodder crops help to improve the economic situation of small and marginal farmers because of higher income. Inclusion of crops in sequential and intercropping systems reduces some obnoxious weeds through formation of canopies due to competitive planting pattern and thus provides an opportunity to utilize cropping systems as a tool of weed management with non-chemical means. Use of organic source not only acts as supplement for fertilizer (nitrogen) but also improve the physico-chemical properties of soils. Production and use of nitrogen rich biomass offer better prospect for supplementing chemical fertilizers on regular basis. Such biological diversity brings yield and economic stability because of its potential for compensation among components of the system. In a particular agro-climatic and resource condition, the identification of most suitable crop sequence is based on its productivity, stability, land use efficiency as well as production efficiency and its performance is chiefly judged in terms of productivity and net return.

Keywords: integrated farming systems, sustainable intensification, system of crop intensification, wheat

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7544 Reduced Switch Count Asymmetrical Multilevel Inverter Topology

Authors: Voodi Kalandhar, Veera Reddy, Yuva Tejasree

Abstract:

Researchers have become interested in multilevel inverters (MLI) because of their potential for medium- and high-power applications. MLIs are becoming more popular as a result of their ability to generate higher voltage levels, minimal power losses, small size, and low price. These inverters used in high voltage and high-power applications because the stress on the switch is low. Even though many traditional topologies, such as the cascaded H-bridge MLI, the flying capacitor MLI, and the diode clamped MLI, exist, they all have some drawbacks. A complicated control system is needed for the flying capacitor MLI to balance the voltage across the capacitor and diode clamped MLI requires more no of diodes when no of levels increases. Even though the cascaded H-Bridge MLI is popular in terms of modularity and simple control, it requires more no of isolated DC source. Therefore, a topology with fewer devices has always been necessary for greater efficiency and reliability. A new single-phase MLI topology has been introduced to minimize the required switch count in the circuit and increase output levels. With 3 dc voltage sources, 8 switches, and 13 levels at the output, this new single- phase MLI topology was developed. To demonstrate the proposed converter's superiority over the other MLI topologies currently in use, a thorough analysis of the proposed topology will be conducted.

Keywords: DC-AC converter, multi-level inverter (MLI), diodes, H-bridge inverter, switches

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7543 Effect of Supplemental Bacterial Phytase at Different Dietary Levels of Phosphorus on Tibial Bone Characteristics and Body Weight Gain in Broilers

Authors: Saqib Saleem Abdullah, Saima Masood, Hafsa Zaneb, Shela Gul Bokhari, Muti Ur Rehman, Jamil Akbar

Abstract:

A 5- weeks feeding trial was carried out to determine the effectiveness of Bacterial Phytase (Phyzyme®) in broilers, at different dietary levels of Phosphorous. 140 d-old broilers (Hubbard) were randomly divided into 4 groups (n=4). Birds were fed corn-based basal diet or the same diet supplemented with 3 different levels of non Phytate Phosphorous (NPP) (0.45 %, 0.30 % and 0.15 %). Furthermore, the diets were supplemented with bacterial Phytase. Birds were fed ad libitum and kept under thermo neutral conditions. The parameters studied were; body weight gain (BWG), tibial bone characteristics (TBC), serum Calcium (Ca), Phosphorus (P) and Alkaline Phosphatase (AP) levels and tibia ash percentage (TAP). BWG of the broilers was calculated at weekly interval and remaining parameters were calculated after slaughtering the birds at 35thday. Results suggested that Phytase supplementation at 0.30% NPP (Non Phytate Phosphorus + Bacterial Phytase) increased (P < 0.05) the BWG, bone length, bone weight, tibiotarsal index, medullary canal diameter and diaphysis diameter however, rubosticity index was reduced to minimum (P < 0.05) at this dietary level of phosphorous when compared with other groups. Maximum (P < 0.05) rubosticity index was observed in control group with 0% Phytase. Furthermore, Phytase addition at 0.30 % NPP also improved (P < 0.05) Ca, P and AP levels in the blood. Phytase supplementation at lower phosphorus level (0.30%NPP) improved BWG and TBC including bone density and bone quality in broilers hence it can be concluded that addition of Phytase at 0.30% NPP may prove beneficial for bone and overall performance in broilers.

Keywords: diaphysis diameter, phytase, rubosticity index, tibia

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7542 Quantification of Pollution Loads for the Rehabilitation of Pusu River

Authors: Abdullah Al-Mamun, Md. Nuruzzaman, Md. Noor Salleh, Muhammad Abu Eusuf, Ahmad Jalal Khan Chowdhury, Mohd. Zaki M. Amin, Norlida Mohd. Dom

Abstract:

Identification of pollution sources and determination of pollution loads from all areas are very important for sustainable rehabilitation of any contaminated river. Pusu is a small river which, flows through the main campus of International Islamic University Malaysia (IIUM) at Gombak. Poor aesthetics of the river, which is flowing through the entrance of the campus, gives negative impression to the local and international visitors. As such, this study is being conducted to find ways to rehabilitate the river in a sustainable manner. The point and non-point pollution sources of the river basin are identified. Upper part of the 12.6 km2 river basin is covered with secondary forest. However, it is the lower-middle reaches of the river basin which is being cleared for residential development and source of high sediment load. Flow and concentrations of the common pollutants, important for a healthy river, such as Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Suspended Solids (SS), Turbidity, pH, Ammoniacal Nitrogen (AN), Total Nitrogen (TN) and Total Phosphorus (TP) are determined. Annual pollution loading to the river was calculated based on the primary and secondary data. Concentrations of SS were high during the rainy day due to contribution from the non-point sources. There are 7 ponds along the river system within the campus, which are severely affected by high sediment load from the land clearing activities. On the other hand, concentrations of other pollutants were high during the non-rainy days. The main sources of point pollution are the hostels, cafeterias, sewage treatment plants located in the campus. Therefore, both pollution sources need to be controlled in order to rehabilitate the river in a sustainable manner.

Keywords: river pollution, rehabilitation, point pollution source, non-point pollution sources, pollution loading

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7541 The Influence of Training and Competition on Cortisol Levels and Sleep in Elite Female Athletes

Authors: Shannon O’Donnell, Matthew Driller, Gregory Jacobson, Steve Bird

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Stress hormone levels in a competition vs. training setting are yet to be evaluated in elite female athletes. The effect that these levels of stress have on subsequent sleep quality and quantity is also yet to be investigated. The aim of the current study was to evaluate different psychophysiological stress markers in competition and training environments and the subsequent effect on sleep indices in an elite female athlete population. The study involved 10 elite female netball athletes (mean ± SD; age = 23 ± 6 yrs) providing multiple salivary hormone measures and having their sleep monitored on two occasions; a match day, and a training day. The training and match were performed at the same time of day and were matched for intensity and duration. Saliva samples were collected immediately pre (5:00 pm) and post session (7:15 pm), and at 10:00 pm and were analysed for cortisol concentrations. Sleep monitoring was performed using wrist actigraphy to assess total sleep time (TST), sleep efficiency (SE%) and sleep latency (SL). Cortisol levels were significantly higher (p < 0.01) immediately post the match vs post training (mean ± SD; 0.925 ± 0.341 μg/dL and 0.239 ± 0.284 μg/dL, respectively) and at 10:00pm (0.143 ± 0.085 μg/dL and 0.072 ± 0.064 μg/dL, respectively, p < 0.01). The difference between trials was associated with a very large effect (ES: 2.23) immediately post (7:15 pm) and a large effect (ES: 1.02) at 10:00 pm. There was a significant reduction in TST (mean ± SD; -117.9 ± 111.9 minutes, p < 0.01, ES: -1.89) and SE% (-7.7 ± 8.5%, p < 0.02, ES: -0.79) on the night following the netball match compared to the training session. Although not significant (p > 0.05), there was an increase in SL following the netball match v the training session (67.0 ± 51.9 minutes and 38.5 ± 29.3 minutes, respectively), which was associated with a moderate effect (ES: 0.80). The current study reports that cortisol levels are significantly higher and subsequent sleep quantity and quality is significantly reduced in elite female athletes following a match compared to a training session.

Keywords: cortisol, netball, performance, recovery

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7540 Responses of Trifolium pratense to Lead Accumulation Under In-Vitro Culture Conditions

Authors: Arash Khorasani Esmaeili, Rosna Mat Taha, Sadegh Mohajer

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Seeds of Trifolium pratense (Red clover) were exposed in vitro for 6 weeks to six levels of lead (Pb) concentrations (0, 50, 100, 150, 200, 250 µM) to analyze the effects on growth, total chlorophyll and total protein contents of grown plants against the lead accumulation. The growth of plants was negatively affected by various levels of lead treatment. The fresh and dry weights, as well as lengths of shoots and roots of grown plants under various lead treatments, were found significantly lower in comparison with the control plants. Total chlorophyll and total soluble protein contents of grown plants under lower concentrations of lead treatment did not show significant differences when compared with the control plants, although they were affected significantly in higher levels of lead accumulation (150-250 µM).

Keywords: trifolium pratense, lead accumulation, chlorophyll content, protein content

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7539 Formal Stress Management Teaching Incorporated into the First Year of a Doctor's Practice: A Career Transition Study of British Foundation Year 1 Doctors

Authors: Edward Ridyard, Vinary Varadarajan

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Background and Aims: The first year as a doctor in any country represents a major career transition in any physician's life. During this period, many physicians concentrate on obtaining clinical skills but may not obtain the important skills necessary to cope with stress. In this study we elucidate stress levels amongst FY1 doctors regarding the transitioning into specialty career choices, working in the NHS and anxiety about future career success. Methods: A prospective single blinded analysis of Foundation Year one (FY1) trainees using a non-mandatory online questionnaire was distributed. No exclusion criteria were applied. The only inclusion criteria was the doctor was in a full-time FY1 post and this was their first job in the UK. A total of n= 22 doctors were included in the study. After data collection, statistical analysis using chi-squared testing was applied. Results: The large majority of FY1 doctors (72.7%) already knew what specialty they wished to pursue (p=0.0001). With regards to their future careers 45.5% of FY1 doctors stated "above average" stress levels. The majority of FY1 doctors (64.3%) stated their stress levels working in the NHS were either "above average" or "high". Finally, 81.8% of respondents know colleagues who have been put off from pursuing specialties due to the stress of competition. Conclusions: A large majority of FY1 doctors already know at this early stage what area they would like to specialise in. With this in mind, a large proportion have above "average" levels of stress with regards to securing this future career path. The most worrying finding is that 64.3% of FY1s stated they had "above average" or "high" stress levels working in the NHS. We therefore recommend formal stress management education to be incorporated into the foundation programme curriculum.

Keywords: stress, anxiety, junior doctor, education

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7538 Determinants of Selenium Intake in a High HIV Prevalence Fishing Community in Bondo District, Kenya

Authors: Samwel Boaz Otieno, Fred Were, Ephantus Kabiru, Kaunda Waza

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A study was done to establish determinants of selenium intake in a high HIV prevalence fishing community in the Pala Bondo district, Kenya. It was established that most of the respondents (61%) were small holder Farmers and Fishermen {χ2 (1, N=386) p<0.000}, and that most of them (91.2%) had up to college level education {χ2.(1, N=386) p<0.000}, while the number of males and females were not significantly different {χ (1, N=386) p=0.263} and 83.5% of respondents were married {χ2 (1, N=386) p=0.000}. The study showed that adults take on average 2.68 meals a day (N=382, SD=0.603), while children take 3.02 meals (N=386, SD=1.031) a day, and that in most households (82.6%) food is prepared by the women {χ2 (1, N=386) p=0.000} and further that 50% of foods eaten in that community are purchased {χ2 (1, N=386)=0.1818, p=0.6698}. The foods eaten by 75.2% of the respondents were Oreochromis niloticus, Lates niloticus, and Sorghum bicolour, 64.1% vegetables and that both children and adults eat same types of food, and further that traditional foods which have become extinct are mainly vegetables (46%). The study established that selenium levels in foods eaten in Pala sub-locations varies with traditional vegetables having higher levels of selenium; for example, Laurnea cornuta (148.5 mg/kg), Cleome gynandra (121.5 mg/kg), Vignia ungulata (21.97 mg/kg), while Rastrineobola argentea (51 mg/kg), Lates niloticus (0), Oreochromis niloticus (0) Sorgum bicolour (19.97 mg/kg), and Sorgum bicolour (0). The study showed that there is an inverse relationship between foods eaten and selenium levels {RR=1.21, p=0.000}, with foods eaten by 75.2% of respondents (Oreochromis niloticus/Lates niloticus) having no detectable selenium. The four soil types identified in the study area had varying selenium levels with pleat loam (13.3 mg/kg), sandy loam (10.7 mg/kg), clay (2.8 mg/kg) and loam (4.8 mg/kg). It was concluded from this study that for the foods eaten by most of the respondents the selenium levels were below Daily Reference Intake.

Keywords: determinants, HIV, food, fishing, Selenium

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7537 Effects of Aerobic Training on MicroRNA Let-7a Expression and Levels of Tumor Tissue IL-6 in Mice With Breast Cancer

Authors: Leila Anoosheh

Abstract:

Aim: The aim of this study was to assess The effects of aerobic training on microRNA let-7a expression and levels of tumor tissue IL-6 in mice with breast cancer. Method: Twenty BALB/c c mice (4-5 weeks,17 gr mass) were cancerous by injection of estrogen-dependent receptor breast cancer cells MC4-L2 and divided into two groups: tumor-training(TT) and tumor-control(TC) group. Then TT group completed aerobic training for 6 weeks, 5 days per week (14-18 m/min). After tumor emersion, tumor width and length were measured by digital caliper every week. 48 hours after the last exercise subjects were killed. Tissue sampling were collected and stored in -70ᵒ. Tumor tissue was homogenized and let-7a expression and IL-6 levels were accounted with Real time-PCR and ELISA Kit respectively. Statistical analysis of let-7a was conducted by the REST software. Repeated measures and independent tests were used to assess tumor size and IL-6, respectively. Results: Tumor size and IL-6 levels were significantly decreased in TT group compare with TC group (p<0.05). microRNA let-7a was increased significantly in TT against control group respectively (p=0/000). Conclusion: Reduction in tumor size, followed by aerobic exercise can be attributed to the loss of inflammatory factors such as IL-6; It seems that regarding to up regulation effects of aerobic exercise training on let-7a and down regulation effects of that on IL-6 in mice with breast cancer, This type of training can be used as adjuvant therapy in conjunction with other therapies for breast cancer.

Keywords: breast cancer, aerobic training, microRNA let-7a, IL-6

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7536 Protective Effect of Bexarotene, a Selective RXRα Agonist, against Hypotension Associated with Inflammation and Tissue Injury Linked to Decreased Circulating iNOS Levels in A Rat Model of Septic Shock

Authors: Bahar Tunctan, Sefika Pinar Kucukkavruk, Meryem Temiz-Resitoglu, Demet Sinem Guden, Ayse Nihal Sari, Seyhan Sahan-Firat

Abstract:

We hypothesized that rexinoids such as bexarotene, a selective retinoid X receptor α (RXRα) agonist, may be beneficial for preventing mortality due to inflammation associated with increased expression/activity of inducible nitric oxide synthase (iNOS) induced by lipopolysaccharide (LPS). Therefore, we investigated effects of bexarotene on the changes in circulating protein levels of iNOS (an index for systemic iNOS expression), myeloperoxidase (MPO) (an index for systemic inflammation), and lactate dehydrogenase (LDH) (an index for systemic tissue injury) in LPS-induced systemic inflammation model resulting in septic shock in rats. Rats were injected with saline (4 ml/kg; i.p.), LPS (10 mg/kg; i.p.), dimethylsulphoxide (4 ml/kg, 0.1%; s.c.) at time 0. Mean arterial blood pressure and heart rate were measured using a tail-cuff device. Bexarotene (0.03, 0.1, 0.3, and 1 mg/kg; s.c.) was administered to separate groups of rats 1 h after injection of saline or LPS. The rats were sacrificed 4 h after saline or LPS injection and blood was collected for measurement of serum iNOS, MPO, and LDH protein levels. Blood pressure decreased by 31 mmHg and heart rate increased by 63 bpm in the LPS-treated rats. Bexarotene at 0.3 and 1 mg/kg doses caused 20% mortality 4 h after LPS injection. In the LPS-treated rats, serum iNOS, MPO, and LDH protein levels were increased. Bexarotene only at 0.1 mg/kg dose prevented the LPS-induced hypotension and increased in iNOS, MPO, and LDH protein levels. These data are consistent with the view that a decrease in systemic iNOS levels contributes to the beneficial effect of bexarotene to prevent the hypotension associated with inflammation and tissue injury during rat endotoxemia. [This work was financially supported by The Scientific and Technological Research Council of Turkey (SBAG-109S121)].

Keywords: bexarotene, inflammation, iNOS, lipopolisaccharide, RXRa

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7535 Implementation of the Circular Economy Concept in Greenhouse Production Systems: Microalgae and Biostimulant Production Using Soilless Crops’ Drainage Nutrient Solution

Authors: Nikolaos Katsoulas, Sofia Faliagka, George Kountrias, Eleni Dimitriou, Eleftheria Pechlivani

Abstract:

The challenges to feed the world in 2050 are becoming more and more apparent. This calls for producing more with fewer inputs (most of them under scarcity), higher resource efficiency, minimum or zero effect on the environment, and higher sustainability. Therefore, increasing the circularity of production systems is highly significant for their sustainability. Protected horticulture offers opportunities for maximum resource efficiency across various levels within and between farms and at the regional level), high-quality production, and contributes significantly to the nutrition security as part of the world food production. In greenhouses, closed soilless cultivation systems give the opportunity to increase the water and nutrient use efficiency and reduce the environmental impact of the cultivation system by the reuse of the drained water and nutrients. However, due to the low quality of the water used in the Mediterranean countries, a completely closed system is not feasible. Partial discharge of the drainage nutrient solution when the levels of electrical conductivity (EC) or of the toxic ions in the system are reached is still a necessity. Thus, in the frame of the circular economy concept, this work presents the utilisation of the drainage solution of soilless cultivation systems for microalgae and biofertilisers production. The system includes a greenhouse equipped with a soilless cultivation system, a drainage solution collection tank, a closed bioreactor for microalgae production, and a biocatalysis tank. The bioreactor tested in the frame of this work includes two closed tube loops of a capacity of 1000 L each where, after the initial inoculation, the microalgae is developed using as a growth medium the drainage solution collected from the greenhouse crops. The bioreactor includes light and temperature control while pH is still manually regulated. As soon as the microalgae culture reaches a certain density level, 20% of the culture is harvested, and the culture system is refiled by a drainage nutrient solution. The microalgae produced goes through a biocatalysis process, which leads to the production of a rich aminoacids (and nitrogen) biofertiliser. The produced biofertiliser is then used for the fertilisation of greenhouse crops. The complete production cycle along with the effects of the biofertiliser produced on crop growth and yield are presented and discussed in this manuscript. Acknowledgment: This work was carried out under the PestNu project that has received funding from the European Union’s Horizon 2020 research and innovation programme under the Green Deal grant agreement No. 101037128 — PestNu.

Keywords: soilless, water use efficiency, nutrients use efficiency, biostimulant

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7534 Aeronautical Noise Management inside an Aerodrome: Analysis of Sound Exposure on Aviation Professional’s Health

Authors: Rafael Felipe Guatura da Silva, José Luis Gomes da Silva, Luiz Antonio, Ferreira Perrone de Brito

Abstract:

Noise can cause serious damage to human health, such as hearing loss, stress, irritability, fatigue, and others. Aviation is a place where your entire process should be work out with the utmost attention and commitment of human resources, thus the need to study the effects of noise in this sector, as aeronautical noise levels are high. This study aimed to evaluate the impact of noise pollution on the performance of professionals regarding the fatigue generated by aeronautical noise and time to noise exposure. The methodology used consists of measurements of sound pressure levels at 42 points of the aerodrome. The selected points are located inside the hangars and outside the airfield hangars. All points chosen are close to the professionals' work areas, seeking to identify the sound pressure levels to which they submitted. The other part of the research used the principle on the application of a self-report questionnaire to a sample of 207 people working inside the aerodrome. The 207 professionals surveyed consist of aircraft mechanics, pilots, maintenance managers, and administrative professionals. The questionnaire was intended to evaluate the knowledge that professionals have about health risks caused by sound exposure as well as to identify diseases that professionals have, and that may be associated with exposure to high levels of sound pressure. Preliminary results identify points with sound pressure levels of up to 91.7 dB, thus highlighting the need for the use of personal protective equipment that reduces noise exposure. It was also identified a large number of professionals who are bothered by the sound exposure and approximately 25% of professionals interviewed reported having a hearing disorder.

Keywords: aeronautical noise, fatigue, noise and health, noise management

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7533 Method for Tuning Level Control Loops Based on Internal Model Control and Closed Loop Step Test Data

Authors: Arnaud Nougues

Abstract:

This paper describes a two-stage methodology derived from internal model control (IMC) for tuning a proportional-integral-derivative (PID) controller for levels or other integrating processes in an industrial environment. Focus is the ease of use and implementation speed which are critical for an industrial application. Tuning can be done with minimum effort and without the need for time-consuming open-loop step tests on the plant. The first stage of the method applies to levels only: the vessel residence time is calculated from equipment dimensions and used to derive a set of preliminary proportional-integral (PI) settings with IMC. The second stage, re-tuning in closed-loop, applies to levels as well as other integrating processes: a tuning correction mechanism has been developed based on a series of closed-loop simulations with model errors. The tuning correction is done from a simple closed-loop step test and the application of a generic correlation between observed overshoot and integral time correction. A spin-off of the method is that an estimate of the vessel residence time (levels) or open-loop process gain (other integrating process) is obtained from the closed-loop data.

Keywords: closed-loop model identification, IMC-PID tuning method, integrating process control, on-line PID tuning adaptation

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7532 Elimination Study of Organic Pollutants from Leachate Technical Landfill; Using Fenton and Photo-Fenton Systems Combined with Biological Treatment

Authors: Belahmadi M. S. O., Abdessemed A., Benchiheub M., Doukali H., Kaid Kasbah K. M.

Abstract:

The aim of this study is to evaluate the quality of leachate generated by the Batna landfill site, and to verify the performance of various advanced oxidation processes, in particular the Fenton and Photo-Fenton systems combined with biological treatment to eliminate the recalcitrant organic matter contained in this effluent, and to preserve reverse osmosis membranes used for leachate treatment. The average values obtained are compared with national and international discharge standards. The results of physico-chemical analyses show that the leachate has an alkaline pH =8.26 and a high organic load with a low oxygen content. Mineral pollution is represented by high conductivity (38.3 mS/cm), high Kjeldahl nitrogen content (1266.504 mg/L) and ammoniacal nitrogen (1098.384 mg/L). The average pollution indicator parameters measured were: BOD5 = 1483.333 mg O2 /L, COD = 99790.244 mg O 2/L, TOC = 22400 mg C/L. These parameters exceed Algerian standards. Hence, there is a necessity to treat this effluent before discharging it into the environment. A comparative study was carried out to estimate the efficiency of two oxidation processes. Under optimum reaction conditions, TOC removal efficiencies of 63.43% and 73.4% were achieved for the Fenton and Photo-Fenton processes, respectively. COD removal rates estimated at 88% and 99.5% for the Fenton and Photo- Fenton processes, respectively. In addition, the Photo-Fenton + bacteria + micro- algae hybrid treatment gave removal efficiencies of around 92.24% for TOC and 99.9% for COD; -0.5 for AOS and 0.01 for CN. The results obtained during this study showed that a hybrid approach combining the PhotoFenton process and biological treatment appears to be a highly effective alternative for achieving satisfactory treatment, which aimed at exploiting the advantages of this method in terms of organic pollutant removal.

Keywords: leachate, landfill, advanced oxidation processes, Fenton and Photo-Fenton systems, biological treatment, organic pollutants

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7531 Assessment of the Fertility Status of the Fadama Soils Found along Five Major River Catchments in Kano

Authors: Garba K. Adamu

Abstract:

This research was carried out in the catchments of five major rivers in Kano State. The catchments have considerable Fadama lands; these include: River Gari which is located in the northwestern part of Kano state, Rivers Challawa and Watari from southernparts of Kano and Katsina states. River Tomas from the northern parts of Kano state, River Jakara which has its source from the Old Kano city, part of Central Business Districts and Industrial Estates. The study was carried out with aim of assessing the fertility status of the Fadama soils found in these major river catchments. A transect was designed to collect samples along farming villages in the five river channels for the study. The findings indicate that the soils are predominantly sandy. The bulk density values vary significantly and range from 0.98mg/m to 1.36mg/m. The pH values for all the sites studied ranges from slightly acidic to slightly alkaline. The OC ranged from low to very low in the sites. The EC ranges from 66.3µs/cm to 198µs/cm for all the sites. The mean CEC ranges from 3.864 cm/kg to 10.114 Cmol/kg. The range of values for the SAR was 0.0106 to 0.069. Nitrogen ranges from0.03 to 0.1230ppm. The range of P value fell between 9.9 to 41.1mg/kg.Ca values ranges from 1.0170 to 14.9850 and K values ranges from 4.6550 – 64.40.Mg values range from 0.1380 to 1.8580 and Zn values range from 1.0170 to 14.9850. The Fe values ranged from 15.6500mg/kg to 69.8000mg/kg. The B values range from0.2060 to13.5450. Generally, the values obtained shows a low to medium fertility levels for all the parameters tested and the areas will require the in cooperation of organic manure and chemical fertilizers to improve soil structure and supplements other macro nutrients.

Keywords: assessment, Fadama soils, fertility status, river catchment

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7530 The Influence of Teachers Anxiety-Reducing Strategies on Learners Foreign Language Anxiety

Authors: Fakieh Alrabai

Abstract:

This study investigated the effects on learner anxiety of anxiety-reducing strategies utilized by English as foreign language teachers in Saudi Arabia. The study was conducted in two stages. In the first stage, sources of foreign language anxiety for Saudi learners of English (N = 596) were identified using The Foreign Language Classroom Anxiety Scale (FLCAS). In the second stage, 465 learners who were divided almost equally into two groups (experimental vs. control) and 12 teachers were recruited. Anxiety-reducing strategies were implemented exclusively in the treatment group for approximately eight weeks. FLCAS was used to assess learners’ FL anxiety levels before and after treatment. Statistical analyses (e.g. ANOVA and ANCOVA) were used to evaluate the study findings. These findings revealed that the intervention led to significantly decreased levels of FL anxiety for learners in the experimental group compared with increased levels of anxiety for those in the control group.

Keywords: communication apprehension, EFL teaching/learning, fear of negative evaluation, foreign language anxiety

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7529 The Impact of Socialization Preferences on Perceptions of Generalized Social Trust in China

Authors: Menghzheng Yao

Abstract:

Generalized social trust among Chinese has been declining in the past few decades, making the search for its causes necessary. Drawing on the symbolic interaction theory and the 2012 Chinese General Social Survey data, this research investigated the impact of people’s socialization preferences and frequencies on their perceptions of generalized social trust in China. This research also took a preliminary step towards understanding the spatial differences of the generalized social trust using the ArcGIS software. The results show that respondents who interacted with their neighbors more frequently were more likely to have higher levels of perceptions of generalized social trust. Several demographics were also significantly related to perception of generalized social trust. Elderly and better educated Chinese and people with higher self-perceived social status were associated with greater levels of generalized social trust perception, while urban dwellers and religious respondents expressed lower levels of such perception. Implications for future research and policy are discussed.

Keywords: China, generalized social trust, symbolic interaction, ArcGIS

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7528 Biostimulant and Abiotic Plant Stress Interactions in Malting Barley: A Glasshouse Study

Authors: Conor Blunt, Mariluz del Pino-de Elias, Grace Cott, Saoirse Tracy, Rainer Melzer

Abstract:

The European Green Deal announced in 2021 details agricultural chemical pesticide use and synthetic fertilizer application to be reduced by 50% and 20% by 2030. Increasing and maintaining expected yields under these ambitious goals has strained the agricultural sector. This intergovernmental plan has identified plant biostimulants as one potential input to facilitate this new phase of sustainable agriculture; these products are defined as microorganisms or substances that can stimulate soil and plant functioning to enhance crop nutrient use efficiency, quality and tolerance to abiotic stresses. Spring barley is Ireland’s most widely sown tillage crop, and grain destined for malting commands the most significant market price. Heavy erratic rainfall is forecasted in Ireland’s climate future, and barley is particularly susceptible to waterlogging. Recent findings suggest that plant receptivity to biostimulants may depend on the level of stress inflicted on crops to elicit an assisted plant response. In this study, three biostimulants of different genesis (seaweed, protein hydrolysate and bacteria) are applied to ‘RGT Planet’ malting barley fertilized at three different rates (0 kg/ha, 40 kg/ha, 75 kg/ha) of calcium ammonium nitrogen (27% N) under non-stressed and waterlogged conditions. This 4x3x2 factorial trial design was planted in a completed randomized block with one plant per experimental unit. Leaf gas exchange data and key agronomic and grain quality parameters were analyzed via ANOVA. No penalty on productivity was evident on plants receiving 40 kg/ha of N and bio stimulant compared to 75 kg/ha of N treatments. The main effects of nitrogen application and waterlogging provided the most significant variation in the dataset.

Keywords: biostimulant, Barley, malting, NUE, waterlogging

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7527 Plasma Pretreatment for Improving the Durability of Antibacterial Activity of Cotton Using ZnO Nanoparticles

Authors: Sheila Shahidi, Hootan Rezaee, Abosaeed Rashidi, Mahmood Ghoranneviss

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Plasma treatment has an explosive increase in interest and use in industrial applications as for example in medical, biomedical, automobile, electronics, semiconductor and textile industry. A lot of intensive basic research has been performed in the last decade in the field of textiles along with technical textiles. Textile manufacturers and end-users alike have been searching for ways to improve the surface properties of natural and man-made fibers. Specifically, there is a need to improve adhesion and wettability. Functional groups may be introduced onto the fiber surface by using gas plasma treatments, improving fiber surface properties without affecting the fiber’s bulk properties. In this research work, ZnO nanoparticles (ZnO-NPs) were insitue synthesized by sonochemical method at room temperature on both untreated and plasma pretreated cotton woven fabric. Oxygen and nitrogen plasmas were used for pre-functionalization of cotton fabric. And the effect of oxygen and nitrogen pre-functionalization on adhesion properties between ZnO nanoparticles and cotton surface were studied. The results show that nanoparticles with average sizes of 20-100 nm with different morphologies have been created on the surface of samples. Synthesis of ZnO-NPs was varied in the morphological transformation by changes in zinc acetate dehydrate concentration. Characterizations were carried out using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Inductive coupled plasma (ICP) and Spectrophotometery. The antibacterial activities of the fabrics were assessed semi-quantitatively by the colonies count method. The results show that the finished fabric demonstrated significant antibacterial activity against S. aureus in antibacterial test. The wash fastness of both untreated and plasma pretreated samples after 30 times of washing was investigated. The results showed that the parameters of plasma reactor plays very important role for improving the antibacterial durability.

Keywords: antibacterial activity, cotton, fabric, nanoparticles, plasma

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7526 Antimicrobial Properties of Copper in Gram-Negative and Gram-Positive Bacteria

Authors: Travis J. Meyer, Jasodra Ramlall, Phyo Thu, Nidhi Gadura

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For centuries humans have used the antimicrobial properties of copper to their advantage. Yet, after all these years the underlying mechanisms of copper mediated cell death in various microbes remain unclear. We had explored the hypothesis that copper mediated increased levels of lipid peroxidation in the membrane fatty acids is responsible for increased killing inEscherichia coli. In this study we show that in both gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa) bacteria there is a strong correlation between copper mediated cell death and increased levels of lipid peroxidation. Interestingly, the non-spore forming gram positive bacteria as well as gram negative bacteria show similar patterns of cell death, increased levels of lipid peroxidation, as well as genomic DNA degradation, however there is some difference inloss in membrane integrity upon exposure to copper alloy surface.

Keywords: antimicrobial, copper, gram positive, gram negative

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7525 Occurrence and Levels of Mycotoxins in On-Farm Stored Sesame in Major-Growing Districts of Ethiopia

Authors: S. Alemayehu, F. A. Abera, K. M. Ayimut, R. Mahroof, J. Harvey, B. Subramanyam

Abstract:

The occurrence of mycotoxins in sesame seeds poses a significant threat to food safety and the economy in Ethiopia. This study aimed to determine the levels and occurrence of mycotoxins in on-farm stored sesame seeds in major-growing districts of Ethiopia. A total of 470 sesame seed samples were collected from randomly selected farmers' storage structures in five major-growing districts using purposive sampling techniques. An enzyme-linked immunosorbent assay (ELISA) was used to analyze the collected samples for the presence of four mycotoxins: total aflatoxins (AFT), ochratoxin A (OTA), total fumonisins (FUM), and deoxynivalenol (DON). The study found that all samples contained varying levels of mycotoxins, with AFT and DON being the most prevalent. AFT concentrations in detected samples ranged from 2.5 to 27.8 parts per billion (ppb), with a mean concentration of 13.8 ppb. OTA levels ranged from 5.0 ppb to 9.7 ppb, with a mean level of 7.1 ppb. Total fumonisin concentrations ranged from 300 to 1300 ppb in all samples, with a mean of 800 ppb. DON concentrations ranged from 560 to 700 ppb in the analyzed samples. The majority (96.8%) of the samples were safe from AFT, FUM, and DON mean levels when compared to the Federal Drug Administration maximum limit. AFT-OTA, DON-OTA, AFT-FUM, FUM-DON, and FUM-OTA, respectively, had co-occurrence rates of 44.0, 38.3, 33.8, 30.2, 29.8 and 26.0% for mycotoxins. On average, 37.2% of the sesame samples had fungal infection, and seed germination rates ranged from 66.8% to 91.1%. The Limmu district had higher levels of total aflatoxins, kernel infection, and lower germination rates than other districts. The Wollega variety of sesame had higher kernel infection, total aflatoxins concentration, and lower germination rates than other varieties. Grain age had a statistically significant (p<0.05) effect on both kernel infection and germination. The storage methods used for sesame in major-growing districts of Ethiopia favor mycotoxin-producing fungi. As the levels of mycotoxins in sesame are of public health significance, stakeholders should come together to identify secure and suitable storage technologies to maintain the quantity and quality of sesame at the level of smallholder farmers. This study suggests the need for suitable storage technologies to maintain the quality of sesame and reduce the risk of mycotoxin contamination.

Keywords: districts, seed germination, kernel infection, moisture content, relative humidity, temperature

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7524 Theoretical Study of Substitutional Phosphorus and Nitrogen Pairs in Diamond

Authors: Tahani Amutairi, Paul May, Neil Allan

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Many properties of semiconductor materials (mechanical, electronic, magnetic, and optical) can be significantly modified by introducing a point defect. Diamond offers extraordinary properties as a semiconductor, and doping seems to be a viable method of solving the problem associated with the fabrication of diamond-based electronic devices in order to exploit those properties. The dopants are believed to play a significant role in reducing the energy barrier to conduction and controlling the mobility of the carriers and the resistivity of the film. Although it has been proven that the n-type diamond semiconductor can be obtained with phosphorus doping, the resulting ionisation energy and mobility are still inadequate for practical application. Theoretical studies have revealed that this is partly because the effects of the many phosphorus atoms incorporated in the diamond lattice are compensated by acceptor states. Using spin-polarised hybrid density functional theory and a supercell approach, we explored the effects of bonding one N atom to a P in adjacent substitutional sites in diamond. A range of hybrid functional, including HSE06, B3LYP, PBE0, PBEsol0, and PBE0-13, were used to calculate the formation, binding, and ionisation energies, in order to explore the solubility and stability of the point defect. The equilibrium geometry and the magnetic and electronic structures were analysed and presented in detail. The defect introduces a unique reconstruction in a diamond where one of the C atoms coordinated with the N atom involved in the elongated C-N bond and creates a new bond with the P atom. The simulated infrared spectra of phosphorus-nitrogen defects were investigated with different supercell sizes and found to contain two sharp peaks at the edges of the spectrum, one at a high frequency 1,379 cm⁻¹ and the second appearing at the end range, 234 cm⁻¹, as obtained with the largest supercell (216).

Keywords: DFT, HSE06, B3LYP, PBE0, PBEsol0, PBE0-13

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