897 research outputs found

    Estudio del déficit hídrico y microorganismos beneficiosos sobre la calidad del aceite y las características agronómicas de la canola (Brassica napus L.)

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    Water deficit stress is one of the major limiting factors that adversely affect plant growth and yield production. Some rhizosphere bacteria are known to promote plant growth in such stressful conditions. To study the response of quantifying canola growth, yield and yield components, to root colonization by two spe­cies of mycorrhizal fungi, a two-year field experiment was conducted at the research farm of Zanjan University. The main plot conditions were irrigation at 85% (S1), 70% (S2) and 55% (S3) of field capacity which were defined as no stress, mild and severe stress. The subplot treatments included three levels of mycorrhizal inoculation: non inoculation (control), G. Mosseae and G. Intraradices. The results showed that regardless of water deficit stress, colonized plants produced more biomass, seed and oil yield than non inoculated plants. Water deficit stress reduced the RWC and oil percentage of the seeds, although mycorrhizal improved these traits. Water deficit strikingly decreased the linoleic acid content in the seeds in contrast with increased stearic, oleic, arachidic and linolenic acids in the canola seeds. The presence of bacteria increased the seed oil percentage, oleic and linoleic contents. However, it decreased arachidic, particularly when the plants were subjected to water deficit stress.El estrés por déficit hídrico es uno de los factores limitantes más importantes que afectan negativamente al crecimiento de las plantas y al rendimiento. Se sabe que algunas bacterias de la rizosfera promueven el crecimiento de las plantas en condiciones estresantes. Para estudiar el crecimiento de la canola, el rendimiento y los componentes del rendimiento, a la colonización de la raíz por dos especies de hongos micorrícicos, se realizó un experimento de campo de dos años en la granja de investigación de la Universidad de Zanjan. Las principales condiciones de la parcela fueron el riego al 85% (S1), 70% (S2) y 55% (S3) de la capacidad de campo, que se definió como sin estrés, estrés leve y severo. Los tratamientos de la subparcela incluyeron tres niveles de inoculación micorrízica: no inoculación (control), G. Mosseae y G. intrara­dices. Los resultados mostraron que, independientemente del estrés por déficit hídrico, las plantas colonizadas producían más biomasa, semillas y rendimiento de aceite que las plantas no inoculadas. El estrés por déficit hídrico reduce el RWC y el porcentaje de semillas oleaginosas, aunque la micorriza mejoró estos rasgos. La existencia de déficit hídrico disminuyó notablemente el contenido de ácido linoleico de la semilla en contraste, aumentaron los ácidos esteárico, oleico, araquídico y linolénico en las semillas de canola. La presencia de bac­terias aumentó el porcentaje de aceite de semilla, el contenido de oleico y linoleico. Sin embargo, disminuye el araquídico particularmente cuando las plantas fueron sometidas a estrés de déficit de agua

    Fungal Enzymes as Catalytic Tools for Polyethylene Terephthalate (PET) Degradation.

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    The ubiquitous persistence of plastic waste in diverse forms and different environmental matrices is one of the main challenges that modern societies are facing at present. The exponential utilization and recalcitrance of synthetic plastics, including polyethylene terephthalate (PET), results in their extensive accumulation, which is a significant threat to the ecosystem. The growing amount of plastic waste ending up in landfills and oceans is alarming due to its possible adverse effects on biota. Thus, there is an urgent need to mitigate plastic waste to tackle the environmental crisis of plastic pollution. With regards to PET, there is a plethora of literature on the transportation route, ingestion, environmental fate, amount, and the adverse ecological and human health effects. Several studies have described the deployment of various microbial enzymes with much focus on bacterial-enzyme mediated removal and remediation of PET. However, there is a lack of consolidated studies on the exploitation of fungal enzymes for PET degradation. Herein, an effort has been made to cover this literature gap by spotlighting the fungi and their unique enzymes, e.g., esterases, lipases, and cutinases. These fungal enzymes have emerged as candidates for the development of biocatalytic PET degradation processes. The first half of this review is focused on fungal biocatalysts involved in the degradation of PET. The latter half explains three main aspects: (1) catalytic mechanism of PET hydrolysis in the presence of cutinases as a model fungal enzyme, (2) limitations hindering enzymatic PET biodegradation, and (3) strategies for enhancement of enzymatic PET biodegradation

    Modification of bacterial cell membrane to accelerate decolorization of textile wastewater effluent using microbial fuel cells: role of gamma radiation

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    The aim of the present work was to increase bacterial adhesion on anode via inducing membrane modifications to enhance textile wastewater treatment in Microbial Fuel Cell (MFC). Real textile wastewater was used in mediator-less MFCs for bacterial enrichment. The enriched bacteria were pre-treated by exposure to 1 KGy gamma radiation and were tested in MFC setup. Bacterial cell membrane permeability and cell membrane charges were measured using noninvasive dielectric spectroscopy measurements. The results show that pre-treatment using gamma radiation resulted in biofilm formation and increased cell permeability and exopolysaccharide production; this was reflected in both MFC performance (average voltage 554.67 mV) and decolorization (96.42%) as compared to 392.77 mV and 60.76% decolorization for non-treated cells. At the end of MFC operation, cytotoxicity test was performed for treated wastewater using a dermal cell line, the results obtained show a decrease in toxicity from 24.8 to 0 (v/v%) when cells were exposed to gamma radiation. Fourier-transform infrared (FTIR) spectroscopy showed an increase in exopolysaccharides in bacterial consortium exposed to increasing doses of gamma radiation suggesting that gamma radiation increased exopolysaccharide production, providing transient media for electron transfer and contributing to accelerating MFC performance. Modification of bacterial membrane prior to MFC operation can be considered highly effective as a pre-treatment tool that accelerates MFC performance

    Investigation of the Bed and Structural Slopes on Bed Shear Stress and Flow Characteristics around an Impermeable Groyne

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    In this paper, effects of the cross shore and groyne wall slopes on flow parameters around an impermeable groyne were considered using a three-dimensional numerical CFD model (i.e., FLUENT). The k-ε turbulence model was used to evaluate the Reynolds stresses. The model was first applied to a vertical groyne on a flat bed and the model results were compared with the relevant experimental data. The results of this numerical test showed good agreements with the corresponding experimental measurements, in terms of water elevation, velocity magnitudes and reattachment length. The model was then applied to a series of structures with different lateral wall slopes on various cross sectional bed slopes. The numerical model results revealed that by increasing the cross shore bed slope in any case of the structural slopes, the magnitude of the maximum velocity and bed shear stresses decreased. These values decreased further as the structural slope reduced

    Gated Recurrent Units for Blockage Mitigation in mmWave Wireless

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    Millimeter-Wave (mmWave) communication is susceptible to blockages, which can significantly reduce the signal strength at the receiver. Mitigating the negative impacts of blockages is a key requirement to ensure reliable and high throughput mmWave communication links. Previous research on blockage mitigation has introduced several model and protocol based blockage mitigation solutions that focus on one technique at a time, such as handoff to a different base station or beam adaptation to the same base station. In this paper, we address the overarching problem: what blockage mitigation method should be employed? and what is the optimal sub-selection within that method? To address the problem, we developed a Gated Recurrent Unit (GRU) model that is trained using periodically exchanged messages in mmWave systems. We gathered extensive amount of simulation data from a commercially available mmWave simulator, show that the proposed method does not incur any additional communication overhead, and that it achieves outstanding results in selecting the optimal blockage mitigation method with an accuracy higher than 93%. We also show that the proposed method significantly increases the amount of transferred data compared to several other blockage mitigation policies

    Evaluation of Confounders in Toxoplasmosis Indirect Fluorescent Antibody Assay

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    Background: The IFA test is one of the most usual methods for detecting anti-Toxoplasma antibod­ies, although it has not any unique standardization. It seems that the microscopic judg­ment of results is an important confounder in IFA test. Therefore, we conducted the present study to clarify the role of microscopic observer, and other confounders on the test.Methods: Eighty sera were collected from patients suspicious to toxoplasmosis for detection IgG anti-T. gondii by this test. Samples were examined against different series of antigens, IgG anti-human conjugates, and observers.Results: There were no significant differences between the two series of antigens and conjugates. For the observers groups the kappa coefficient of the test results in the experts group (0.97, 0.94-1.00) were significantly higher than the less experienced observers (0.77, 0.68-0.87).Conclusion: We recommend the IFA test to be performed only in reference laboratories and by laboratory technicians that have enough experience for this test. Otherwise, we suggest the substitution of this test with other tests like ELISA for the diagnosis and epidemiological studies
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