9 research outputs found
Adaptive Fuzzy Supplementary Controller for SSR Damping in a Series-Compensated DFIG-Based Wind Farm
Although using a series compensation technique in a long transmission line effectively increases the transmittable power; it may cause a sub-synchronous resonance (SSR) phenomenon. Gate-controlled series capacitor (GCSC) is an effective method for SSR damping by controlling the turn-off angle. In the previous studies, a constant supplementary damping controller (SDC) was used for controlling the turn-off angle, which can mitigate the SSR phenomenon. However, these methods can not capture the maximum transmittable power at different operating points. In this paper, a fuzzy logic controller (FLC) is proposed to compute the gain of SDC based on the wind speed and the error between the measured and reference line currents for transferring as much power as possible and damping the SSR phenomenon simultaneously. Using the MATLAB/SIMULINK program, the proposed method is tested at different operating points to validate its effectiveness and robustness. Compared to the traditional method (constant SDC), the maximum transmittable power, as well as SSR damping, is achieved in all studied cases by the proposed method (variable SDC)
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Treatment of Sweet Pepper with Stress Tolerance-Inducing Compounds Alleviates Salinity Stress Oxidative Damage by Mediating the Physio-Biochemical Activities and Antioxidant Systems
Salinity stress occurs due to the accumulation of high levels of salts in soil, which ultimately leads to the impairment of plant growth and crop loss. Stress tolerance-inducing compounds have a remarkable ability to improve growth and minimize the effects of salinity stress without negatively affecting the environment by controlling the physiological and molecular activities in plants. Two pot experiments were carried out in 2017 and 2018 to study the influence of salicylic acid (1 mM), yeast extract (6 g L−1), and proline (10 mM) on the physiological and biochemical parameters of sweet pepper plants under saline conditions (2000 and 4000 ppm). The results showed that salt stress led to decreasing the chlorophyll content, relative water content, and fruit yields, whereas electrolyte leakage, malondialdehyde (MDA), proline concentration, reactive oxygen species (ROS), and the activities of antioxidant enzymes increased in salt-stressed plants. The application of salicylic acid (1 mM), yeast extract (6 g L−1), and proline (10 mM) markedly improved the physiological characteristics and fruit yields of salt-stressed plants compared with untreated stressed plants. A significant reduction in electrolyte leakage, MDA, and ROS was also recorded for all treatments. In conclusion, our results reveal the important role of proline, SA, and yeast extracts in enhancing sweet pepper growth and tolerance to salinity stress via modulation of the physiological parameters and antioxidants machinery. Interestingly, proline proved to be the best treatment.</jats:p
Differential Effects of Low-Dose Erythropoietin in Rat Model of Diabetic Nephropathy: Submitted: Jan 3, 2018 Accepted: Feb 26, 2018 Published online: Mar 3, 2018
Background. Previous reports on the renoprotective effect of erythropoietin (EPO) in the setting of chronic kidney disease (CKD) have yielded conflicting results. The aim of this study is to clarify the effect of low, non-hematopoietic dose of EPO on the evolution of diabetic nephropathy (DN) in rat model. Methods. Low dose of recombinant human EPO (150 U/kg, s.c. three times/week) was given to streptozotocin (STZ)-induced diabetic rats in two schedules; in the first one, EPO was given from day 2 after STZ injection till the end of the study (28 weeks) as prophylactic treatment; and in the other schedule EPO was given after development of DN (last 8 weeks) as therapeutic treatment. Albuminuria, blood pressure, creatinine clearance, renal venous oxygen tension (vPO2), plasma EPO, hematocrit and renal histopathology were assessed. Results. Unexpectedly, 28 weeks administration of EPO to diabetic rats led to aggravation of albuminuria and worsening of histopathological damage in spite of partial correction of renal hypoxia. Contrary to this, terminal 8 weeks EPO therapy of DN reduced albuminuria and demonstrated some favorable effects on biochemical changes and histologic picture. Conclusion. Low dose EPO exerted differential effects in rat model of DN according to treatment duration. In addition, findings of the present study warrants further investigations of the exact renoprotective role of EPO in diabetic patients with CKD who receive EPO therapy for long periods
Morpho-Physiological and Anatomical Alterations of Salt-Affected Thompson Seedless Grapevine (Vitis vinifera L.) to Brassinolide Spraying
Salinity is one of the most critical crises worldwide that ultimately compromises future food security. Brassinosteroids including brassinolide (BL) are a class of polyhydroxy steroids phytohormones, that play a crucial role in several plant metabolic pathways and boost plants’ stress tolerance, but less data is accessible on its function in salt-affected grapevine. The experiment was conducted throughout the 2019 and 2020 experimental seasons at EL-Baramon experimental farm, Horticulture Research Institute, Mansoura, Egypt, to recognize the remediation potential of BL (1 and 2 mg L−1) in lightening salinity (NaCl at 1000, 2000, and 3000 mg L−1) injury on Thompson seedless grapevine seedlings (H4 strain) growth and physio-anatomical attributes. Data advocated that while salinity reduced growth attributes, BL applications substantially improved the overall salt-affected plant performance. Salinity stress significantly decreased photosynthetic pigment, relative water content, and ions percentage (nitrogen, phosphorus, potassium, potassium/sodium ratio). Alternatively, BL spraying significantly (p ≤ 0.05) increased the photosynthetic pigment, maintaining a favorable potassium/sodium ratio and increasing the ions percentage. Additionally, increasing salinity levels significantly boost plant sodium percentage and induce a membrane malfunction associated with increased membrane permeability; conversely, the application of BL decreased the sodium percentage associated with decreasing membrane permeability relative to non-treated salinized plants. Moreover, salinity and/or BL significantly improved the antioxidant capacity associated with rising proline accumulation and antioxidant enzyme activities. Anatomically, salinity stress considerably modified leaf structure; meanwhile, the spraying with BL drastically mitigates the harmful effects of salinity on leaf anatomy. Additionally, salt-affected plant cells explained various obvious organelles ultrastructural modifications and cellular damage; meanwhile, BL spraying to salt-affected plants repealed the ultrastructural modifications of cell organelles. Taken together, BL, especially 2 mg L−1, has a great potential to boost the salt tolerance of Thompson seedless grapevine seedlings (H4 strain). It improves salt tolerance by sustaining higher photosynthetic pigment concentrations, maintaining ion homeostasis, regulating water status, and stimulating antioxidant capacity as well as maintaining leaf anatomical attributes
Treatment of Sweet Pepper with Stress Tolerance-Inducing Compounds Alleviates Salinity Stress Oxidative Damage by Mediating the Physio-Biochemical Activities and Antioxidant Systems
Salinity stress occurs due to the accumulation of high levels of salts in soil, which ultimately leads to the impairment of plant growth and crop loss. Stress tolerance-inducing compounds have a remarkable ability to improve growth and minimize the effects of salinity stress without negatively affecting the environment by controlling the physiological and molecular activities in plants. Two pot experiments were carried out in 2017 and 2018 to study the influence of salicylic acid (1 mM), yeast extract (6 g L−1), and proline (10 mM) on the physiological and biochemical parameters of sweet pepper plants under saline conditions (2000 and 4000 ppm). The results showed that salt stress led to decreasing the chlorophyll content, relative water content, and fruit yields, whereas electrolyte leakage, malondialdehyde (MDA), proline concentration, reactive oxygen species (ROS), and the activities of antioxidant enzymes increased in salt-stressed plants. The application of salicylic acid (1 mM), yeast extract (6 g L−1), and proline (10 mM) markedly improved the physiological characteristics and fruit yields of salt-stressed plants compared with untreated stressed plants. A significant reduction in electrolyte leakage, MDA, and ROS was also recorded for all treatments. In conclusion, our results reveal the important role of proline, SA, and yeast extracts in enhancing sweet pepper growth and tolerance to salinity stress via modulation of the physiological parameters and antioxidants machinery. Interestingly, proline proved to be the best treatment
Pre and postharvest characteristics of Dahlia pinnata var. pinnata, cav. As affected by SiO2 and CaCO3 nanoparticles under two different planting dates
Agriculture faces many challenges because of climate changes. The nutrients present in nano-sized form improve plant productivity, especially when used at the appropriate planting time. Field experiments were conducted as a factorial experiment for evaluating two planting dates (20th September and 20th October), foliar application with nanoparticles (NPs) including silica nanoparticles (SiO2-NPs) at 1.5 and 3 mM, calcium carbonate nanoparticles (CaCO3-NPs) at 5 and 10 mM and distilled water (control) on pre- and post-harvest characteristics of Dahlia pinnata var. pinnata Cav. The results indicate that the interactions during the late planting time (20th October) and exogenous applications of SiO2-NPs at 1.5 mM or CaCO3-NPs at 10 mM have improved plant growth including plant height, stem diameter, fresh and dry weights of plant, leaf area, inflorescence diameter, inflorescence stalk length, branches number, tuber numbers, inflorescences number on the plant, and the vase life. At the same time, insignificant differences appeared in the interaction during the planting dates and SiO2 or CaCO3 -NPs concentrations on inflorescence stalk diameter, total soluble solids, membrane stability index, maximum increase in fresh weight (FW), and Si and Ca contents. In addition, all exogenous applications of NPs at the late planting time promoted the plant growth characteristics like lignin %, cellulose %, inflorescence water content, change in FW, and total water uptake. Moreover, the controls through the two planting dates recorded the maximum change in water uptake and water loss values. In short, it can be recommended to use SiO2-NPs at 1.5 mM or CaCO3-NPs at 10 mM as a foliar application at the late planting time (20th October) for obtaining the optimum quantitative and qualitative parameters of D. pinnata
Anatomical and Physiological Performance of Jojoba Treated with Proline under Salinity Stress Condition
A field trial study was conducted for two consecutive seasons 2020 and 2021 in approximately 8-month-old jojoba plants to evaluate the physiological responses following salt treatment and the role of proline as a foliar application to enhance jojoba tolerance to salinity stress. Jojoba plants were irrigated once a week for four months with diluted seawater in concentrations of 5000, 10,000, and 15,000 ppm and tap water (control). Anti-stress proline was applied four times throughout the experiment, the first at the beginning of the experiment and another three times at 30-day intervals, at concentrations of 0, 300, and 450 ppm. The effect of proline treatments on jojoba plant behavior includes growth vegetative characteristics, namely plant height increase percentage (PHIP), shoot number increase percentage (NSIP), stem diameter increase percentage (SDIP), number of leaves, leaf thickness, leaf area, and fresh and dry weights of leaves, and chemical characteristics, namely chlorophyll a and b, total chlorophyll, carotenoids, leaf mineral contents (N, P, K, Na, and Cl), total phenolic content (TPC), and proline concentration. Moreover, the impacts of proline on hydrogen peroxide (H2O2), superoxide anion (O2•−), malondialdehyde (MDA), and ion leakage (IL) under salinity stress were investigated. Briefly, proline at 450 ppm enhanced all studied growth and physiological characteristics and promoted the antioxidant system of jojoba plants compared with the control and other treatments. The anatomical structure of leaves was also examined, and favorable variations in the anatomical structure were detected in the stressed and proline-treated plants. Exogenous application of proline enhanced most of this anatomical characteristic of jojoba leaf under saline stress. In conclusion, proline as a foliar application at 450 ppm under salinity stress of 10,000 ppm enhances jojoba tolerance to salinity stress by modifying the physicochemical and morphological characteristics of jojoba plants
Efficiency of Candida tropicalis for Potential Degradation of Metalaxyl in the Aqueous Media
Physicians' guideline adherence is associated with long-term heart failure mortality in outpatients with heart failure with reduced ejection fraction: the QUALIFY international registry
Background: Physicians' adherence to guideline-recommended therapy is associated with short-term clinical outcomes in heart failure (HF) with reduced ejection fraction (HFrEF). However, its impact on longer-term outcomes is poorly documented. Here, we present results from the 18-month follow-up of the QUALIFY registry. Methods and results: Data at 18 months were available for 6118 ambulatory HFrEF patients from this international prospective observational survey. Adherence was measured as a continuous variable, ranging from 0 to 1, and was assessed for five classes of recommended HF medications and dosages. Most deaths were cardiovascular (CV) (228/394) and HF-related (191/394) and the same was true for unplanned hospitalizations (1175 CV and 861 HF-related hospitalizations, out of a total of 1541). According to univariable analysis, CV and HF deaths were significantly associated with physician adherence to guidelines. In multivariable analysis, HF death was associated with adherence level [subdistribution hazard ratio (SHR) 0.93, 95% confidence interval (CI) 0.87–0.99 per 0.1 unit adherence level increase; P = 0.034] as was composite of HF hospitalization or CV death (SHR 0.97, 95% CI 0.94–0.99 per 0.1 unit adherence level increase; P = 0.043), whereas unplanned all-cause, CV or HF hospitalizations were not (all-cause: SHR 0.99, 95% CI 0.9–1.02; CV: SHR 0.98, 95% CI 0.96–1.01; and HF: SHR 0.99, 95% CI 0.96–1.02 per 0.1 unit change in adherence score; P = 0.52, P = 0.2, and P = 0.4, respectively). Conclusion: These results suggest that physicians' adherence to guideline-recommended HF therapies is associated with improved outcomes in HFrEF. Practical strategies should be established to improve physicians' adherence to guidelines. © 2019 The Authors. European Journal of Heart Failure © 2019 European Society of Cardiolog