118 research outputs found

    Power System Stabilizer Driven by an Adaptive Fuzzy Set for Better Dynamic Performance

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    This paper presents a novel application of a fuzzy logic controller (FLC) driven by an adaptive fuzzy set (AFS) for a power system stabilizer (PSS).The proposed FLC, driven by AFS, is compared with a classical FLC, driven by a fixed fuzzy set (FFS). Both FLC algorithms use the speed error and its rate of change as input vectors. A single generator equipped with FLC-PSS and connected to an infinite bus bar through double transmission lines is considered. Both FLCs, using AFS and FFS, are simulated and tested when the system is subjected to different step changes in the reference value. The simulation results of the proposed FLC, using the adaptive fuzzy set, give a better dynamic response of the overall system by improving the damping coefficient and decreasing the rise time and settling time compared with classical FLC using FFS. The proposed FLC using AFS also reduces the computational time of the FLC as the number of rules is reduced.

    Water Salinity Impacts on Some Soil Properties and Nutrients Uptake by Wheat Plants in Sandy and Calcareous Soil

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    S and S , respectively. Results concluded that, the lower germination percentage and rate in calcareous soil at any salinity level compared to sandy soil. and also, decreased the mean daily germination in both soils. Soil salinity increased as a result of increasing salinity levels of irrigation water. Easily available 1 4 water were negatively correlated with increasing water salinity from S to S , especially in case of calcareous soil. Same trend was observed in case of soluble cations and anions; especially Na which increased by 121, 285, 610 % and 94, 267, 531 % for S , S and S relative to the control, for sandy and 3 calcareous soils, respectively. The higher N, P uptake were attained in calcareous soil under (S ) while, the lowest were found in sandy soil under higher water salinity levels indicating the resistibility of Sakha 8 as wheat cultivar to salinity level up to 6.60 dSm . Substantial decrease of K:Na ratio of wheat was found grain yield by 23 %, while to 16 % reduction is found in calcareous soil. The yield reduction increases by increasing salinity of irrigation water and reaches its maximum at 8.86 dSm salinity level. Grain yield, -1 was highly significant negative correlated with hardly available water, water salinity and soil EC, while the relations were highly positive with easily available water

    Neutrophil depletion reduces edema formation and tissue loss following traumatic brain injury in mice

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    Background: Brain edema as a result of secondary injury following traumatic brain injury (TBI) is a major clinical concern. Neutrophils are known to cause increased vascular permeability leading to edema formation in peripheral tissue, but their role in the pathology following TBI remains unclear. Methods: In this study we used controlled cortical impact (CCI) as a model for TBI and investigated the role of neutrophils in the response to injury. The outcome of mice that were depleted of neutrophils using an anti-Gr-1 antibody was compared to that in mice with intact neutrophil count. The effect of neutrophil depletion on blood-brain barrier function was assessed by Evan's blue dye extravasation, and analysis of brain water content was used as a measurement of brain edema formation (24 and 48 hours after CCI). Lesion volume was measured 7 and 14 days after CCI. Immunohistochemistry was used to assess cell death, using a marker for cleaved caspase-3 at 24 hours after injury, and microglial/macrophage activation 7 days after CCI. Data were analyzed using Mann-Whitney test for non-parametric data. Results: Neutrophil depletion did not significantly affect Evan's blue extravasation at any time-point after CCI. However, neutrophil-depleted mice exhibited a decreased water content both at 24 and 48 hours after CCI indicating reduced edema formation. Furthermore, brain tissue loss was attenuated in neutropenic mice at 7 and 14 days after injury. Additionally, these mice had a significantly reduced number of activated microglia/macrophages 7 days after CCI, and of cleaved caspase-3 positive cells 24 h after injury. Conclusion: Our results suggest that neutrophils are involved in the edema formation, but not the extravasation of large proteins, as well as contributing to cell death and tissue loss following TBI in mice

    Sustained axon regeneration induced by co-deletion of PTEN and SOCS3

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    A formidable challenge in neural repair in the adult central nervous system (CNS) is the long distances that regenerating axons often need to travel in order to reconnect with their targets. Thus, a sustained capacity for axon regeneration is critical for achieving functional restoration. Although deletion of either phosphatase and tensin homologue (PTEN), a negative regulator of mammalian target of rapamycin (mTOR), or suppressor of cytokine signalling 3 (SOCS3), a negative regulator of Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway, in adult retinal ganglion cells (RGCs) individually promoted significant optic nerve regeneration, such regrowth tapered off around 2 weeks after the crush injury. Here we show that, remarkably, simultaneous deletion of both PTEN and SOCS3 enables robust and sustained axon regeneration. We further show that PTEN and SOCS3 regulate two independent pathways that act synergistically to promote enhanced axon regeneration. Gene expression analyses suggest that double deletion not only results in the induction of many growth-related genes, but also allows RGCs to maintain the expression of a repertoire of genes at the physiological level after injury. Our results reveal concurrent activation of mTOR and STAT3 pathways as key for sustaining long-distance axon regeneration in adult CNS, a crucial step towards functional recovery

    Selectivity control in Pt-catalyzed cinnamaldehyde hydrogenation

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    Chemoselectivity is a cornerstone of catalysis, permitting the targeted modification of specific functional groups within complex starting materials. Here we elucidate key structural and electronic factors controlling the liquid phase hydrogenation of cinnamaldehyde and related benzylic aldehydes over Pt nanoparticles. Mechanistic insight from kinetic mapping reveals cinnamaldehyde hydrogenation is structure-insensitive over metallic platinum, proceeding with a common Turnover Frequency independent of precursor, particle size or support architecture. In contrast, selectivity to the desired cinnamyl alcohol product is highly structure sensitive, with large nanoparticles and high hydrogen pressures favoring C=O over C=C hydrogenation, attributed to molecular surface crowding and suppression of sterically-demanding adsorption modes. In situ vibrational spectroscopies highlight the role of support polarity in enhancing C=O hydrogenation (through cinnamaldehyde reorientation), a general phenomenon extending to alkyl-substituted benzaldehydes. Tuning nanoparticle size and support polarity affords a flexible means to control the chemoselective hydrogenation of aromatic aldehydes

    Neurogenic inflammation after traumatic brain injury and its potentiation of classical inflammation

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    Background: The neuroinflammatory response following traumatic brain injury (TBI) is known to be a key secondary injury factor that can drive ongoing neuronal injury. Despite this, treatments that have targeted aspects of the inflammatory pathway have not shown significant efficacy in clinical trials. Main body: We suggest that this may be because classical inflammation only represents part of the story, with activation of neurogenic inflammation potentially one of the key initiating inflammatory events following TBI. Indeed, evidence suggests that the transient receptor potential cation channels (TRP channels), TRPV1 and TRPA1, are polymodal receptors that are activated by a variety of stimuli associated with TBI, including mechanical shear stress, leading to the release of neuropeptides such as substance P (SP). SP augments many aspects of the classical inflammatory response via activation of microglia and astrocytes, degranulation of mast cells, and promoting leukocyte migration. Furthermore, SP may initiate the earliest changes seen in blood-brain barrier (BBB) permeability, namely the increased transcellular transport of plasma proteins via activation of caveolae. This is in line with reports that alterations in transcellular transport are seen first following TBI, prior to decreases in expression of tight-junction proteins such as claudin-5 and occludin. Indeed, the receptor for SP, the tachykinin NK1 receptor, is found in caveolae and its activation following TBI may allow influx of albumin and other plasma proteins which directly augment the inflammatory response by activating astrocytes and microglia. Conclusions: As such, the neurogenic inflammatory response can exacerbate classical inflammation via a positive feedback loop, with classical inflammatory mediators such as bradykinin and prostaglandins then further stimulating TRP receptors. Accordingly, complete inhibition of neuroinflammation following TBI may require the inhibition of both classical and neurogenic inflammatory pathways.Frances Corrigan, Kimberley A. Mander, Anna V. Leonard and Robert Vin

    Role of the lesion scar in the response to damage and repair of the central nervous system

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    Traumatic damage to the central nervous system (CNS) destroys the blood-brain barrier (BBB) and provokes the invasion of hematogenous cells into the neural tissue. Invading leukocytes, macrophages and lymphocytes secrete various cytokines that induce an inflammatory reaction in the injured CNS and result in local neural degeneration, formation of a cystic cavity and activation of glial cells around the lesion site. As a consequence of these processes, two types of scarring tissue are formed in the lesion site. One is a glial scar that consists in reactive astrocytes, reactive microglia and glial precursor cells. The other is a fibrotic scar formed by fibroblasts, which have invaded the lesion site from adjacent meningeal and perivascular cells. At the interface, the reactive astrocytes and the fibroblasts interact to form an organized tissue, the glia limitans. The astrocytic reaction has a protective role by reconstituting the BBB, preventing neuronal degeneration and limiting the spread of damage. While much attention has been paid to the inhibitory effects of the astrocytic component of the scars on axon regeneration, this review will cover a number of recent studies in which manipulations of the fibroblastic component of the scar by reagents, such as blockers of collagen synthesis have been found to be beneficial for axon regeneration. To what extent these changes in the fibroblasts act via subsequent downstream actions on the astrocytes remains for future investigation

    Neurogenic inflammation after traumatic brain injury and its potentiation of classical inflammation

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    Composting of Rice Straw and its Influences on Iron Availability in Calcareous Soil

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    Abstract: Composting incubation and pot experiment were conducted to evaluate the nutritional status of composted rice straw mixed with organic raw materials and assess the combined effect of compost and iron supply on growth, yield, and iron status of barley plant grown in calcareous soil. Results indicated that, the determination of humification parameters (HA, FA and DH), C/N ratio and temperature could be used to evaluate the quality of composted rice straw mixed with different raw material. The compost 2 of rice straw mixture (M ) with chicken manure registered the best regarding its nutritional values and narrower in C/N ratio and humification degree. The C/N ratio showed very high positive significant correlation with TOC and HA indicating their role for narrowing the C/N ratio for the composted materials. Whereas, the degree of humification had highly positive significant correlation with soluble and available iron by releasing chelated compounds during composting. Results of pot experiment clarified that, 2 the effectiveness of application of composted rice straw with chicken manure (M ) gave the highest grain, straw yield of barley in calcareous soil. Iron uptake and ferrous iron increased significantly due to 2 compost supply (M ) and foliar spray of 0.25 % citric acid over other treatments. Successive extraction of iron at 40 days in calcareous soil of barley plant showed significant effect from compost application on water soluble, exchangeable, acid soluble and organically bound iron. This increment of iron fraction in soil and iron uptake by plant was associated with a predominate increase in chlorophyll content of barley leaves correcting the iron deficiency symptoms in calcareous soil
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