366 research outputs found

    Evaluation the Antimicrobial Activity of Artemisia and Portulaca Plant Extracts in Beef Burger

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    Medicinal plants contain substances can alternate the traditional chemical preservatives which used for preserving meat products that have negative effects on consumer health. Several biological activities have been reported for Artemisia and Portulaca as antimicrobial agents, so the current study focused on using Artemisia and Portulaca extracts as antimicrobial agents in beef burger. Phytochemical of Artemisia and Portulaca extracts were analyzed, and both extracts contain alkaloids, flavonoids, phenols, trepenoids and saponin. The results show that Artemisia extract was inhibited all tested microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella Typhimurium, Listeria monocytogenes and E.coli O157:H7) while, Portulaca extract affect Staphylococcus aureus only. The Minimum Cidal Concentration (MCC) and Minimum Inhibitory Concentration (MIC) were carried out for testing microorganisms, since Artemisia extract was very effective against Staphylococcus aureus followed by E.coli, Pseudomonas aeruginosa, Salmonella Typhimurium and L. monocytogenes. Artemisia and Portulaca extracts were separately applied in beef burger as antimicrobials at levels 1% and 1.5%. The sensory evaluation of treated beef burger showed no significant differences between control sample and treatments containing Portulaca extract while, the addition of Artmesia extract had a detrimental effect on taste of beef burger since it causes formation of bitter taste

    THE HYDROGEN-FUELLED INTERNAL COMBUSTION ENGINES FOR MARINE APPLICATIONS WITH A CASE STUDY

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    Modern marine power plants have been designed to improve the overall ship’s efficiency. This pushed the designers of marine machinery to search for unconventional fuels for these plants. During the previous years, diesel oil has been extensively used on-board ships. Due to the high price of light diesel oil and the environmental problems resulting from the use of heavy fuel oil, it has become necessary to search for an alternative to traditional fuels. As a result, natural gas fuel has been used on-board some types of ships, especially short-voyage cruise ships. Unfortunately, there are still some technical and logistic problems related to the use of natural gas as a fuel, especially as it is considered a non-renewable energy source. The use of hydrogen fuel on-board ships, particularly in modern power plants may contribute to overcoming the above problems. The present paper considers the possibility of the use of hydrogen fuel for marine applications and discusses different stages of hydrogen gas cycle beginning with hydrogen generation process from clean energy until using it as fuel for internal combustion engines on-board one RO/RO ship, named Taba, operating in the Mediterranean Sea. Compared to the diesel engine, the hydrogen fuelled engine is found to be lower in thermal efficiency and fuel consumption, however, some adjustments are needed

    An efficient technique for out-of-band power reduction for the eliminated CP-STC-shaped system for 5G requirements

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    The most dominant needs for the recent wireless mobile applications are higher bandwidth (BW) efficiency, higher energy efficiency higher quality of services (QOS). The main technique in 4G systems is OFDM but it suffers from some limitations such as large peak to average power ratio (PAPR), higher Out-of-Band (OOB) power radiation, and wasting bandwidth efficiency due to cyclic prefix (CP) extension. In his paper, these OFDM limitations will be reduced with low computational complexity compared to filter bank multicarriers (FBMC). The proposed scheme is based on symbol time compression (STC) for OFDM system. The proposed STC-Shaped system is achieved via interleaver-spreader and symbol shaper in the transmitter side in addition to equalization and combining processes in the receiver side. Comparative study between the proposed system and the conventional OFDM in case of additive white Gaussian noise (AWGN) and COST 207 typical multipath fading channel will be presented. The numerical results show that the proposed STC-Shaped scheme reduces OOB significantly. The proposed scheme improves BER in multipath Rayleigh fading although it is without CP. Thus, the proposed system is more robust against inter symbol interference (ISI) compared to conventional OFDM system. Also, the numerical results show that the PAPR of the proposed system is decreased significantly and also, it is derived theoretically. Also, the proposed scheme overcomes CP extension, and hence increases the bandwidth (BW) efficiency. Finally, the computational complexity for the proposed scheme is derived and it has very low complexity compared to FBMC. The system performance measurments has been fulfilled using cumulative distribution function (CDF), power spectral density (PSD) and bit error rate (BER)

    Effects of shade level and microenvironment on vegetative growth, physiological and biochemical characteristics of transplanted cucumber (Cucumis sativus)

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    Growing vegetables through transplantation under black shade nets is currently becoming popular to provide protection from high intensities of light and high temperatures. This study evaluated the effects of shade level on microenvironment, vegetative growth, photosynthetic pigments, chlorophyll a fluorescence, osmoprotectants, plant water status and leaf mineral nutrients of greenhouse-grown summer cucumber transplants at 25%, 50%, 63%, and 75% shade levels. Solar radiation and tempera-ture decreased with increased shading levels. Average daily temperatures were approximately decreased by 1.5oC under 75% shade nets compared to the 25% shade nets. Vegetative growth characteristics, photosynthetic pigments, chlorophyll a fluorescence (Fv/Fm, Fv/F0, and PI), dehydration tolerance and Leaf N, P and K concentrations increased when shade level increased. Chlorophyll a fluorescence (Fv/Fm, Fv/F0, and PI) reduced with the increase of solar radiation levels. Also, clear decreases in free proline, soluble sugars and total free amino acids in both experiments with increased shade level have been observed. Additionally, relative water content (RWC), membrane stability index (MSI) and electrolyte leakage (EL) of cucumber transplants were significantly affected in both experiments by shade level. Moreover Shade level affected leaf mineral nutrient but the effect differed among nutrients concentration. This study concluded that, nets with higher shading levels (63 and/or 75%) are a potential alternative to alleviate photo-inhibition and heat stress in cucumber transplants production

    Impact of Clustering Microgrids on Their Stability and Resilience during Blackouts

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    In this paper, the impact of clustering multiple microgrids during blackouts, on their stability and supply availability, will be investigated. Microgrids have the capability of satisfying their emergency loads during blackouts. However, distributed energy resources (DERs)-dominated microgrids are affected by the uncertainty of their input energy supply, e.g. impact of solar irradiance on photovoltaic (PV) output. Moreover, an individual islanded microgrid is prone to instability issues due to large sudden load/generation changes. In order to increase the supply security, and enhance system stability, we propose to use the existing distribution grid infrastructure, if applicable, during blackouts to form microgrid clusters. The paper discusses the required control hierarchy required to manage the microgrid clusters, and communicate with the Distribution Network Operator (DNO). A case study based on the 13-bus standard distribution feeder, and two microgrid models, is presented. Results show that microgrids clustering helps improve their performance and that the microgrid generator inertia has a direct impact on the stability of the microgrid cluster

    Left atrial and left atrial appendage functional recovery after cardioversion in patients with recent atrial fibrillation: Serial echocardiographic study

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    Background: The aim of this study is to point out timing of left atrium and its appendage functional recovery after cardioversion (CV) in recent onset atrial fibrillation (AF). Methods: Fifty patients; 27 within 48-h (group I) and 23 after 48-h (group II), of AF onset, who had successful CV underwent transthoracic echocardiography (TTE), before and im­mediately after CV, then 15, 30 and 90 days later. Transesophageal echocardiography (TEE) was performed for group II before and for all patients immediately after CV and 1 month later. Mitral peak A velocity and left atrial (LA) reversal (Ar) velocity, tissue Doppler imaging (TDI) of septal mitral annular velocity (A1) and LA free wall velocity (A3) were recorded. Absence or peak A velocity < 50 cm/s was taken as a cut off value for atrial stunning. Intra-atrial conduction time (IACT) was measured. LA appendage late emptying (LAALE) velocity was measured by TEE-pulsed TDI of LA appendage. Results: Post CV, all group II and 34% of group I experienced stunning. In both groups, peak A, Ar, A1, A3 and LAALE velocities increased (p = 0.000), while IACT decreased (p = 0.000) progressively over time. Partial recovery occurred after 15 and 30 days, while full recovery occurred 30 and 90 days post CV in groups I and II, respectively. IACT1 and IACT2 correlated with LA diameter (r = 0.2778 and r = 0.227, respectively, p < 0.01). Conclusions: Stunning and functional recovery of the LA and its appendage are strongly determined by the duration being in AF. Serial IACT by TDI was a good new parameter for detection of functional recovery of LA and LA appendage

    Utilization of LSTM neural network for water production forecasting of a stepped solar still with a corrugated absorber plate

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    This study introduces a long short-term memory (LSTM) neural network model to forecast the freshwater yield of a stepped solar still and a conventional one. The stepped solar still was equiped by a copper corrugated absorber plate. The thermal performance of the stepped solar still is compared with that of conventional single slope solar still. The heat transfer coefficients of convection, evaporation, and radiation process have been evaluated. The exergy and energy efficiencies of both solar stills have been also evaluated. The yield of the stepped solar still is enhanced by about 128 % compared with that of conventional solar still. Then, the proposed LSTM neural network method is utilized to forecast the hourly yield of the investigated solar stills. Field experimental data was used to train and test the developed model. The freshwater yield was used in a time series form to train the proposed model. The forecasting accuracy of the proposed model was compared with those obtained by conventional autoregressive integrated moving average (ARIMA) and was evaluated using different statistical assessment measures. The coefficient of determination of the forecasted results has a high value of 0.97 and 0.99 for the conventional and the stepped solar still, respectively

    The etiology of neuromuscular fatigue induced by the 5-m shuttle run test in adult soccer players

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    This study investigated the etiology of neuromuscular fatigue induced by a 5-m shuttle run test (5MSRT) in soccer players. Nineteen adult male amateur soccer players (age: 20.0 ± 2.9 years) participated in the present study. Before and after the 5MSRT, they were instructed to complete a maximal voluntary isometric contraction (MVIC) of the knee extensors (KE) during and after which two electrical stimulations were applied at the femoral nerve. Voluntary activation level (VAL), surface electromyography recordings (sEMG), electrophysiological (Mmax) and potentiated resting twitch (Ptw) responses of the KE were compared between pre- and post-5MSRT. Rating of perception exertion (RPE) was also assessed before, during the test immediately following each sprint repetition and after the test. The distance covered during each sprint significantly decreased as the number of trials performed increased (p<.05). The RPE reported following each sprint significantly increased throughout the test. In addition, MVIC (-9%), sEMG (-23%), VAL (-15%), Ptw (-26%) and Mmax (~22%) of the KE were lowered from pre-to-post 5MSRT (.001 < p < .01). The 5MSRT induced a decrease of repeated-sprint running performance and MVIC of the KE. These decrements were accompanied by lowered VAL, sEMG, Ptw and Mmax values of the KE reflecting the involvement of both the central and peripheral origins in the 5MSRT-induced fatigue. Given the important muscle stress induced by 5MSRT, this strenuous test must be applied with caution, after an inevitable familiarization phase, and not during the competition period to avoid the risk of serious injury

    Current Status Regarding Tumour Progression, Surveillance, Diagnosis, Staging, and Treatment Of HCC: A Literature Review

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    Hepatocellular carcinoma (HCC) is the most common primary malignant tumour of the liver, and is globally considered to be a major causes of cancer-associated mortality. The early diagnosis of HCC improves overall survival through the application of suitable treatment options. This article presents some of the techniques for the surveillance of HCC like ultrasonography and the use of tumour biomarkers such as α-fetoprotein (AFP), DesGamma-Carboxy Prothrombin (DCP) and others. Included in the discussion will be diagnostic methods like computed tomography (CT), magnetic resonance imaging (MRI), contrast enhancement ultrasound (CEUS), and fluorodeoxyglucose positron emission tomography hybrid with computed tomography (FDG PET/CT). Current molecular pathogenesis related to HCC and the molecular steps that determine the transition from benign to malignancy are also analysed. The HCC stages which depends on the Barcelona Clinic Liver Cancer (BCLC) algorithm are also discussed. Finally, this review article discusses the present therapeutic and treatment options for HCC such as resection, transplantation, or ablation used to treat early stage cancer. Also included will be trans-arterial chemoembolization (TACE) and Sorafenib for patients with intermediate and advanced-stage cancer, respectively
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