1,385 research outputs found

    Opportunistic Spectrum Sharing using Dumb Basis Patterns: The Line-of-Sight Interference Scenario

    Full text link
    We investigate a spectrum-sharing system with non-severely faded mutual interference links, where both the secondary-to-primary and primary-to-secondary channels have a Line-of-Sight (LoS) component. Based on a Rician model for the LoS channels, we show, analytically and numerically, that LoS interference hinders the achievable secondary user capacity. This is caused by the poor dynamic range of the interference channels fluctuations when a dominant LoS component exists. In order to improve the capacity of such system, we propose the usage of an Electronically Steerable Parasitic Array Radiator (ESPAR) antenna at the secondary terminals. An ESPAR antenna requires a single RF chain and has a reconfigurable radiation pattern that is controlled by assigning arbitrary weights to M orthonormal basis radiation patterns. By viewing these orthonormal patterns as multiple virtual dumb antennas, we randomly vary their weights over time creating artificial channel fluctuations that can perfectly eliminate the undesired impact of LoS interference. Because the proposed scheme uses a single RF chain, it is well suited for compact and low cost mobile terminals

    The role of chamomile oil against ochratoxin A in quail breeders: productive and reproductive performances, egg quality and blood metabolites

    Get PDF
    This study aimed to evaluate the beneficial role of chamomile essential oil in improving productive and reproductive performances, egg quality, and blood metabolites and reducing the toxic effect of Ochratoxin A (OTA) in quail breeder's diets. A total of 144 mature quails, 8 wk old, were divided into 6 groups. The treatments were: G1 (the control), G2 (supplemented with OTA 1 mg/kg diet), G3 (supplemented with chamomile oil 0.5 g/kg diet), G4 (supplemented with chamomile oil 1 G/kg diet), G5 (supplemented with OTA 1 mg/kg diet + chamomile oil 0.5 g/kg diet), and G6 (supplemented with OTA 1 mg/kg diet + chamomile oil 1 g/kg diet). The OTA administration alone significantly decreased egg production and mass in quail breeders (P < 0.0001). Moreover, poor feed conversion ratio (FCR), fertility percentage (P < 0.0001), and hatchability percentage (P < 0.0009) were recorded. A significant decline (P < 0.05) in the levels of serum protein (total protein and globulin) was also recorded in OTA-contaminated groups, along with elevated serum levels of liver enzymes such as alanine transaminase (ALT) and Aspartate transaminase (AST) and kidney function test as urea and creatinine levels (P < 0.05). Ochratoxin A-contaminated feed resulted in a significant elevation (P < 0.05) in total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL), along with a significant reduction (P < 0.05) in antioxidant status and immunological response. The supplementation of chamomile essential oil, either 0.5 g/kg or 1g/kg, to the basal diet or OTA-supplemented feed, revealed a significant increase in hatchability %, fertility, egg mass, and egg production and better FCR, egg quality, and immunological status when compared to OTA only. Moreover, chamomile essential oil supplementation improves liver and kidney function markers, decreases LDL, VLDL), TG, and TC. Along with a significant increase (P < 0.05) in terms of antioxidant status as glutathione peroxidase enzyme (GPX), total antioxidant capacity (TAC), and superoxide dismutase (SOD) and significantly (P < 0.05) improves immunological response as IgM, IgG, lysozyme and complement 3. In summary, chamomile oil supplementation, either separate or combined with OTA, reduced the adverse effects of OTA and led to improved productive and reproductive performance, egg quality, and blood metabolites in Japanese quail breeders

    Dietary supplementation of quercetin nanoparticles enhances the growth performance hematological and immunological responses and resistance to Aeromonas hydrophila infection in Nile tilapia (Oreochromis niloticus) exposed to silver nanoparticles toxicity

    Get PDF
    The wide incorporation of silver nanoparticles (AgNPs) in aquaculture could result in releasing of these particles into the environment with environmental impacts and health hazards. Thus, this study aimed to investigate the impacts of the dietary supplementation of quercetin nanoparticles (QNPs) on Nile tilapia (Oreochromis niloticus) growth, antioxidants, and immunity besides its susceptibility to the infection with Aeromonas hydrophila with or without the aqueous exposure to AgNPs. First, the 96-h LC50 value for AgNPs in O. niloticus wa estimated to be 19.81 mg/L (the 1/10th of the 96 h LC50 of AgNPs = 1.98 mg/L). Then a total of 240 Nile tilapias (40.00 ± 0.45 g) were randomly distributed into 4 groups (each group contains 60 fish in 3 replicates of 20 fish). The 1st group (control) was fed on a basal diet without QNPs and AgNPs. The 2nd group (QNPs) received the basal diet supplemented with QNPs (400 mg/kg), the 3rd group (AgNPs) was exposed to 1/10th 96-h LC50 of AgNPs (1.98 mg/L) and fed on QNPs free diet, while the 4th group (AgNPs+ QNPs) was exposed to AgNPs (1.98 mg/L) and cosupplemented with QNPs (400 mg/kg). Besides, AgNPs resulted in marked elevation in the serum myeloperoxidase (MPO) 8-hydroxy-2-deoxyguanosine (8-OHdG) contents, and declines in lysozyme activity and the levels of nitric oxide (NO) and immunoglobulins (IgM and IgG) in the exposed fish (AgNPs group). These effects were accompanied with significant downregulation in the relative mRNA expressions of SOD, CAT, and GSH and upregulation in the expressions of INF-γ, TNF-α, and Il-1β. Feeding QNPs-enriched diet, alone or combined with AgNPs exposure, conversed most of these effects and restored some to the control levels. AgNPs exposure increased mortalities, lowered survival rates and altered Nile tilapia’s resistance to A. hydrophila infection in the AgNPs exposed fish, whereas co-supplementation with QNPs enhanced their resistance with less mortalities. In summary, the reported immunomodulation, and protective properties of QNPs dietary supplementation, strengthen its applicability as an effective and promising feed supplement to alleviate the AgNPs associated toxicity in fish

    Leverage of Matricaria chamomilla L. Oil Supplementation over Ochratoxin A in Growing Quails

    Get PDF
    Ochratoxin A (OTA) is one of the mycotoxins in the agriculture and livestock sectors. The poultry sector su3ered from significant economic losses due to the adverse impacts of OTA on the growth rate, feed conversion ratio, and livability. Thus, the present investigation aimed to determine the impact of chamomile essential oil supplementation against OTA toxicity in growing quails. 360 one-week-old growing quails were distributed into six groups (n = 60) with four replicates of 15 birds. The groups were G1 (control negative), G2 (OTA 1 mg/kg diet, control positive), G3 (chamomile oil 0.5 g/kg diet), G4 (chamomile oil 1 g/kg diet), G5 (OTA 1 mg/kg diet + chamomile oil 0.5 g/kg diet), and G6 (OTA 1 mg/kg diet + chamomile oil 1 g/kg diet). Adding OTA significantly (P < 0.05) reduced live body weight and weight gain at 5 weeks. Feed intake at 5 weeks was non significantly reduced in G3 and G4 compared to G1. G4 showed a significant (P < 0.05) increase in weight gain and the lowest feed conversion ratio. The G2 showed the lowest superoxide dismutase (SOD), total antioxidant capacity (TAC), glutathione transferase (GST) activity, and the highest levels of malondialdehyde (MDA). Moreover, they showed a significant improvement in liver enzymes and kidney function tests and a significant (P < 0.05) reduction in the levels of total cholesterol and triglycerides. Chamomile supplementation alone or with OTA significantly (P < 0.05) increased immunoglobulin M, G, A, and complement 3 than OTA alone. Chamomile oil with an OTA diet or alone reduced the negative effects of OTA and improved the performance, antioxidant status, lipid profile, and immunological state of growing Japanese quails

    Asymmetric Dimethylation of Ribosomal S6 Kinase 2 Regulates Its Cellular Localisation and Pro-Survival Function

    Get PDF
    Ribosomal S6 kinases (S6Ks) are critical regulators of cell growth, homeostasis, and survival, with dysregulation of these kinases found to be associated with various malignancies. While S6K1 has been extensively studied, S6K2 has been neglected despite its clear involvement in cancer progression. Protein arginine methylation is a widespread post-translational modification regulating many biological processes in mammalian cells. Here, we report that p54-S6K2 is asymmetrically dimethylated at Arg-475 and Arg-477, two residues conserved amongst mammalian S6K2s and several AT-hook-containing proteins. We demonstrate that this methylation event results from the association of S6K2 with the methyltransferases PRMT1, PRMT3, and PRMT6 in vitro and in vivo and leads to nuclear the localisation of S6K2 that is essential to the pro-survival effects of this kinase to starvation-induced cell death. Taken together, our findings highlight a novel post-translational modification regulating the function of p54-S6K2 that may be particularly relevant to cancer progression where general Arg-methylation is often elevated
    corecore