3,336 research outputs found

    Improvement of drought tolerance in five different cultivars of Vicia faba with foliar application of ascorbic acid or silicon

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    Aim of study: To explore the role of ascorbic acid (AsA) or silicon (Si) in improving drought tolerance in five faba bean cultivars under irrigation water deficit (IWD).Area of study: The experimental farm; 30° 36′ N, 32° 16′ E, Egypt.Material and methods: Three drip irrigation regimes (WW, well-watered, 4000 m3 water ha-1; MD, moderate drought, 3000 m3 water ha-1; and SD, severe drought, 2000 m3 water ha-1) were applied to plants, which were sprayed 25, 40, and 55 days after sowing with 1.5 mM AsA or 2.0 mM Si vs distilled water as a control.Main results: Drought negatively affected physiological attributes (photosynthetic pigments, gas exchange parameters, relative water content, membrane stability index, electrolyte leakage (EL), and lipid peroxidation), which restricted plant growth and yields, and stimulated alterations in both enzymatic and non-enzymatic antioxidant activities. However, AsA or Si application mitigated drought effects on physiological attributes, improving growth, yields and water use efficiency by raising antioxidant activities and suppressing lipid peroxidation and EL in stressful cultivars. The mitigating effects of AsA and Si were more pronounced under MD.Research highlights: ‘Nubaria-2’, ‘Giza-843’, and ‘Sakha-3’ were more tolerant than ‘Giza-716’ and ‘Sakha-4’, suggesting the use of AsA or Si to ameliorate the IWD effects on stressful cultivars. Certain physiological traits exhibited positive association with growth and seed yield, demonstrating their importance in enhancing seed yield under irrigation treatments

    Vertical Muscle Transposition with Augmentation for Treatment of Exotropia Caused by Iatrogenic Lost Medial Rectus Muscle

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    Purpose: To evaluate the results of vertical muscle transposition with augmentation in cases of exotropia caused by iatrogenic lost medial rectus muscle. Methods: This is a retrospective review of 5 cases of lost medial rectus with exotropia and marked limitation of adduction that underwent surgery. All cases had a history of strabismus surgery on the medial rectus and failed attempt at retrieval of the lost muscle. Results: Five patients fulfilled the criteria. Full tendon vertical muscle transposition with augmentation sutures was done for all cases. Surgery led to a significant reduction of the angle of exotropia 25.8±13.6 ?D (P=0.027) and improvement in adduction of 7.5±3.8 degrees (P=0.034). There were no complications. Conclusions: Isolated vertical muscle transposition with augmentation is a useful option to improve the exotropia and adduction deficit in patients with iatrogenic lost medial rectus muscle

    Evaluation of two freshwater macrophytes, Ceratophyllum demersum and Potamogeton amplifoliusas feed ingredients for Nile tilapia (Oreochromis niloticus) fingerlings

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    The present study was carried out to evaluate the potential of two common freshwater macrophytes (Ceratophyllum demersum and Potamogeton amplifolius) as feed ingredients for Nile tilapia fingerlings, in two consecutive experiments. The first experiment investigated the use of raw, dried C. demersum and P. amplifolius as sources of energy in the diets of fingerlings. The macrophytes were incorporated in 6 isonitrogenous and isocaloric diets at four levels as a replacement of dietary wheat bran. The test diets were fed to triplicate groups, stocked in 140 L culture aquaria in a recirculating system, three times a day to satiation, for 45 days. The results showed that control, macrophyte-free diet produced significantly improved growth rates and feed utilization efficiency than macrophytes-based diets. In Experiment 2, fermented C. demersum and P. amplifolius were incorporated into six isonitrogenous and isocaloric diets. The diets were fed to triplicate groups of fingerlings (35 g) for 45 days. Growth rates and feed utilization efficiency of fish fed with fermented P. amplifolius at 33 % and 66 % inclusion level were not significantly different from fish fed the control diet. At 100 % inclusion level, fish performance was significantly reduced. On the other hand, fermented C. demersum produced extremely poor performance, compared to raw ceratophyllum. In conclusion, the present results indicated that fermentation improved the quality of P. amplifolius; but not C. demersum

    Evaluation of two freshwater macrophytes, Ceratophyllum demersum and Potamogeton amplifoliusas feed ingredients for Nile tilapia (Oreochromis niloticus) fingerlings

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    37-43The present study was carried out to evaluate the potential of two common freshwater macrophytes (Ceratophyllum demersum and Potamogeton amplifolius) as feed ingredients for Nile tilapia fingerlings, in two consecutive experiments. The first experiment investigated the use of raw, dried C. demersum and P. amplifolius as sources of energy in the diets of fingerlings. The macrophytes were incorporated in 6 isonitrogenous and isocaloric diets at four levels as a replacement of dietary wheat bran. The test diets were fed to triplicate groups, stocked in 140 L culture aquaria in a recirculating system, three times a day to satiation, for 45 days. The results showed that control, macrophyte-free diet produced significantly improved growth rates and feed utilization efficiency than macrophytes-based diets. In Experiment 2, fermented C. demersum and P. amplifolius were incorporated into six isonitrogenous and isocaloric diets. The diets were fed to triplicate groups of fingerlings (35 g) for 45 days. Growth rates and feed utilization efficiency of fish fed with fermented P. amplifolius at 33 % and 66 % inclusion level were not significantly different from fish fed the control diet. At 100 % inclusion level, fish performance was significantly reduced. On the other hand, fermented C. demersum produced extremely poor performance, compared to raw ceratophyllum. In conclusion, the present results indicated that fermentation improved the quality of P. amplifolius; but not C. demersum

    Using negative velocity feedback controller to reduce the vibration of a suspended cable

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    The system of suspended cable with mixed excitation forces is controlled in this paper by using negative linear velocity feedback controller. The equations of motion of this system contain quadratic and cubic nonlinearities. The multiple scale perturbation technique is applied to determine the response of the nonlinear system near the simultaneous sub-harmonic and combined resonance case of this system. The stability of the obtained numerical solution is investigated using frequency response equations. The effect of different parameters on the vibrating system are investigated and reported

    Influence of certain carbon and nitrogen sources on antagonistic potentiality of Trichoderma harzianum and Bacillus subtillus against Botrytis allii the incitant of onion neck rot

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    Gliotoxin Fermentation Agar (GFA) Medium and Nutrient Glucose Agar   (NGA) medium with different carbon and nitrogen sources were used to study the impact of carbon and nitrogen sources on Trichoderma harzianum Rifai and Bacillus subtillus Cohn antagonistic efficiency against growth of Botrytis allii Munn. Results indicated that Trichoderma harzianum gave the highest inhibition % in growth of Botrytis allii when Sucrose was used as a carbon source while the lowest values of inhibition% were appeared by application of Mannitol as a carbon source. Trichoderma harzianum gave the highest inhibition% in growth of B.allii when use Potassium nitrate  as a nitrogen source while the lowest values of inhibition% in growth of B.allii were obtained by application of Beef extract as a nitrogen source. Results showed also that Bacillus subtillus gave the highest inhibition% in growth of B.allii when Mannitol was used as a carbon source while the lowest values of inhibition% in growth of B.allii were appeared by application of Sucrose as a carbon source. Bacillus subtillus gave the highest inhibition% in growth of B.allii when use Glutamic acid as a nitrogen source while the lowest values of inhibition% in growth of B.allii were appeared by application of Tryptophan as a nitrogen source.

    On modeling two immune effectors two strain antigen interaction

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    In this paper we consider the fractional order model with two immune effectors interacting with two strain antigen. The systems may explain the recurrence of some diseases e.g. tuberculosis (TB). The stability of equilibrium points are studied. Numerical solutions of this model are given. Using integer order system the system oscillates. Using fractional order system the system converges to a stable internal equilibrium. Ulam-Hyers stability of the system has been studied

    A nontraditional method for reducing thermoelastic stresses of variable thickness rotating discs

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    Funding Open access funding provided by The Science, Technology & Innovation Funding Authority (STDF) in cooperation with The Egyptian Knowledge Bank (EKB). This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Peer reviewedPublisher PD

    Computational assessment of ballistic impact on a high strength structural steel/polyurea composite plate

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    Ballistic impact on a polyurea retrofitted high strength structural steel plate is simulated and validated. A soft material model for polyurea, which is capable of capturing complex mechanical behavior characterized by large strains, hysteresis, rate sensitivity, stress softening (Mullins effect), and deviatoric and volumetric plasticity, is calibrated against several uniaxial tension experiments and a threedimensional release wave experiment to capture both the material point and bulk behaviors. A porous plasticity model is employed to model the high strength structural steel and localization elements are included to capture adiabatic shear bands and strain localization. The computational capabilities of these models are demonstrated by the prediction of the target plate displacement, which shows excellent agreement with experiments

    Role of hydrogen in volatile behaviour of defects in SiO2-based electronic devices

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    Charge capture and emission by point defects in gate oxides of metal–oxide–semiconductor field-effect transistors (MOSFETs) strongly affect reliability and performance of electronic devices. Recent advances in experimental techniques used for probing defect properties have led to new insights into their characteristics. In particular, these experimental data show a repeated dis- and reappearance (the so-called volatility) of the defect-related signals. We use multiscale modelling to explain the charge capture and emission as well as defect volatility in amorphous SiO2 gate dielectrics. We first briefly discuss the recent experimental results and use a multiphonon charge capture model to describe the charge-trapping behaviour of defects in silicon-based MOSFETs. We then link this model to ab initio calculations that investigate the three most promising defect candidates. Statistical distributions of defect characteristics obtained from ab initio calculations in amorphous SiO2 are compared with the experimentally measured statistical properties of charge traps. This allows us to suggest an atomistic mechanism to explain the experimentally observed volatile behaviour of defects. We conclude that the hydroxyl-E′ centre is a promising candidate to explain all the observed features, including defect volatility
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