132 research outputs found

    Dynamic response of a laterally-loaded infinite rigid cylinder embedded in a saturated poroelastic medium

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    In this paper, an analytical solution for the response of a rigid cylinder embedded in a full-space poroelastic medium subjected to a dynamic lateral load is derived. The problem is idealised as a two-dimensional problem. The solution is obtained using Biot’s theory for acoustic waves. In this solution, the displacements of the solid skeleton and the pore pressure are expressed in terms of three scalar potentials. These potential correspond to the wave velocities of the slow and fast compressional wave and to the shear wave. The governing equation for the dynamic motion is expressed in the frequency domain using Fourier transformation and the potentials are shown to be given by Holmholtz equations

    Changes in pulmonary function in patients with ulcerative colitis

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    SummaryObjectivesInformation on the occurrence and frequency of pulmonary involvement in patients with ulcerative colitis (UC) is inconsistent. Some authors reported pulmonary impairment with UC by standard pulmonary function tests (PFTs) and documented a reduced diffusing capacity for carbon monoxide (DLCO) especially in patients with active disease, whereas others could not detect differences in routine PFTs between UC patients and controls.AimThe aim of this prospective study was to determine the frequency and type of pulmonary dysfunction in patients with UC with respect to disease activity. Furthermore, to evaluate the influence of smoking, nutritional status, sputum cytology and sulphasalazine therapy on PFT parameters.Patients and methodsTwenty-six patients with UC (20 with active disease, 6 inactive) and 16 age and sex matched healthy controls were investigated with respect to the following pulmonary function tests, forced vital capacity (FVC), forced expiratory volume in the 1s (FEV1%) and their ratio (FEV1/FVC) and forced expiratory flow 25–75% (FEF25–75%) as well as oxygen saturation. For UC patients, colonoscopy and biopsy were done. Disease activity was assessed by Truelove index for UC. Induced sputum was sampled for cytology. Smoking habit, body mass index (BMI) and medications were recorded.ResultsFifteen out of 26 patients with UC (57.6%) exhibited at least one pathological pulmonary function test (<80% of predicted value). Small airway obstruction was reported in the 15 patients, restrictive dysfunction in 30.7% and obstructive dysfunction in 11.5%. The impairment of PFTs was significant and more pronounced in patients with active disease, FVC (−14% of predicted), FEV1 (−9% of predicted) and FEF25–75% (−32% of predicted), P<0.01, 0.05 and 0.01, respectively. There was no significant influence of smoking and medications on PFTs.ConclusionsUC patients show significantly decreased lung function tests in comparison to healthy controls. The impairment in active disease exceeded that during the remission. Early recognition is important, as they can be strikingly steroid responsive

    Effect of Trichoderma reesei degraded date pits on antioxidant enzyme activities and biochemical responses of broiler chickens

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    The long-term use of antimicrobials as growth promoters in poultry feed leads to antimicrobial resistance in pathogens. Thus, alternatives to antibiotics are essential for reasons associated with both safety and cost-effectiveness. Underutilized plant sources need to be developed to replace antibiotics in broiler feed. Several feed resources have been introduced so far, but they have yet to be applied widely. Date pits are a major by-product of the date industry (6–8%) and have the potential antioxidant to replace antibiotics. In this study, fresh date pits were degraded using the mold Trichoderma reesei under solid-state degradation (SSD), resulting in degraded date pits (DDP). A total of 180 Brazilian “Cobb 500” broiler chicks were divided into six feed treatments in triplicate groups. The treatments were corn-soy basal diet (positive control; C+), corn-soy + 20% oxytetracycline at 0.05% (negative control; C–), corn-soy + 10% DDP, corn-soy + 0.2% mannan-oligosaccharides (MOS), corn-soy + 0.1% mannose, and corn-soy + 0.2% mannose. The antioxidant and biochemical effects of DDP, MOS, and mannose were determined in the blood serum, liver, and intestine of broilers at age 21 and 42 days. The results indicated that the contents of antioxidants such as flavonoids and phenolics, as well as the MOS content in DDP, were increased by the degradation process. Additionally, mannose, glucose, arabinose, rhamnose, and glucuronic acid were significantly increased in DDP after degradation. The activity of antioxidant enzymes (GPx—glutathione peroxidase, catalase, and SOD—superoxide dismutase) in the serum, liver, and intestine of broilers fed with diets containing 10% DDP and 0.2% MOS was increased significantly compared to the control group. Malondialdehyde activity was decreased, whereas the mean corpuscular hemoglobin level and the iron content were significantly upregulated in the broilers fed with 10% DDP, 0.1% mannose, and 0.2% MOS diets compared with the control. Thus, DDP can be used to improve the antioxidant status and has a prebiotic-like effect in broiler chicken performance

    Intestinal development and histomorphometry of broiler chickens fed Trichoderma reesei degraded date seed diets

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    A study was conducted to investigate the impact of degraded date pits (DDP) on the development and morphology of the intestine in broilers. Trichoderma reesei was used to produce the DDP using a solid-state degradation method. One hundred and eighty broilers were divided into six treatments in triplicate groups of 10 chicks each. The dietary treatments were: positive control with corn-soy basal diet, negative control with corn-soy basal diet + 20% oxytetracycline at 0.05%, corn-soy basal diet + 10% DDP, corn-soy basal diet + 0.2% mannan-oligosaccharides (MOS), corn-soy basal diet + 0.2% mannose and corn-soy basal diet + 0.1% mannose for 6 weeks. The results indicate that a 10% DDP diet increased the activities of the pancreatic enzymes, the villus length, and the villus/crypt ratio, and decreased the crypt depth of the intestine. In conclusion, when compared to oxytetracycline and MOS, DDP can be used as a replacement for antibiotic growth promoters for broilers while improving gut development and intestinal health

    EVALUATION OF WHEAT FLOUR BLENDED WITH DIFFERENT RATIOS OF MORINGA OLEIFERA LEAVES AND SEEDS

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    Chemical composition, minerals content, amino acids, fiber fractions, fatty acids profile, total phenols, total flavonoids and antioxidant activity were determined in wheat flour (WF) 72%, moringa leaves powder (MLP), defatted moringa seeds powder (DMSP) and moringa seeds (MS). Pasting profile and rheological properties of blends supplemented with MLP at levels of 3, 6, 9 and 12% or DMSP at levels of 5, 10, 15 and 20% were also studied. The highest moisture and carbohydrate contents were found in WF (12.60 and 85.05%), respectively. MLP had higher ash and fiber contents (8.87 and 7.91%), respectively, while, protein and fat contents were higher in DMSP and in MS. Mineral content (Ca, K, Mg, P, Na and Fe) in MLP was the highest, while DMSP was higher in Zn content than that of other samples. Fiber fractions of WF were lower than that of both MLP and DMSP. Total essential amino acids of DMSP was higher (19.25%) than that of MLP and WF (12.45 and 4.16%), respectively. Oleic acid was the predominant fatty acid (66.85%) in moringa seeds oil. MLP had the highest value of total phenolic, total flavonoid and antioxidant activity (11.97, 8.02 and 15.87 mg/g), respectively. Color measurements showed that all of MLP, DMSP and WF blends decreased in L*, a*,however, they increased in b*, saturation, hue and ∆E values.    Supplementation with MLP and DMSP at all levels decreased the peak viscosity, trough, breakdown, final and setback viscosities. While, it increased water absorption, dough development time, mixing tolerance index and dough weakening. On contrary, arrival time and dough stability were decreased. Also, MLP and DMSP decreased the extensibility, resistance to extension, maximum resistance to extension energy of dough and the proportional number

    Thermal performance enhancement of a flat plate solar collector using hybrid nanofluid

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    Covalent Functionalized-Multi wall carbon nanotubes (CF-MWCNTs) and Covalent Functionalized-graphene nanoplatelets (CF-GNPs) with hexagonal boron nitride (h-BN) were suspended in distilled water to prepare the hybrid nanofluids as working fluids inside the Flat Plate Solar Collector (FPSC). Different concentrations of the hybrid nanoparticles were considered and Tween-80 (Tw-80) was used as a surfactant. The stability and thermophysical properties were tested using different measurement tools. The structural and morphological properties were examined using FTIR, XRD, UV–vis spectrometry, HRTEM, FESEM, and EDX. The thermal efficiency of FPSC were tested under different volumetric flow rates (2 L/min, 3 L/min, and 4 L/min), whereas the efficiency of the collector was determined based on ASHRAE standard 93-2010. As a result, the most thermal-efficient solar collector improved up to 85% with hybrid nanofluid as the absorption medium at 4 L/min flow rate. Increment in nanoparticles’ concentrations enhanced thermal energy gain and resulted in higher fluid outlet temperature

    Vibration induced memory effects and switching in ac-driven molecular nanojunctions

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    We investigate bistability and memory effects in a molecular junction weakly coupled to metallic leads with the latter being subject to an adiabatic periodic change of the bias voltage. The system is described by a simple Anderson-Holstein model and its dynamics is calculated via a master equation approach. The controlled electrical switching between the many-body states of the system is achieved due to polaron shift and Franck-Condon blockade in the presence of strong electron-vibron interaction. Particular emphasis is given to the role played by the excited vibronic states in the bistability and hysteretic switching dynamics as a function of the voltage sweeping rates. In general, both the occupation probabilities of the vibronic states and the associated vibron energy show hysteretic behaviour for driving frequencies in a range set by the minimum and maximum lifetimes of the system. The consequences on the transport properties for various driving frequencies and in the limit of DC-bias are also investigated.Comment: 15 pages, 20 figures, published versio
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