73 research outputs found
Hyperchaos in acetylcholinesterase enzyme systems
Burst generation via a complex bifurcation scenario is discussed using a two compartments model of an enzyme system with substrate inhibition kinetics affected by the production of hydrogen ions accompanying the reaction (e.g. acetylcholinesterase enzyme system). Evidences are given to support the existence of homoclinicity associated with this complex dynamics, including the generalised criterion developed by Rossler et al. [1] for the application of Sil'nikov's theorem in the case of four-dimensional systems. Complex bi-stabilities are observed in certain regions, and the structure of some attracting sets occurring near homoclinic orbits are discussed. The results support the use of such fundamental models for different dynamical modes generation and analysis. The results relate to the transition of small and large frequency oscillations to periodic bursting and vice versa in excitable cells and many biophysical systems
The effects of external disturbances on the performance and chaotic behaviour of industrial FCC units
The dynamic behaviour of an industrial Type IV fluid catalytic cracking for the production of gasoline unit is investigated for a case where the air feed temperature is periodically forced. The investigation concentrates on the behaviour of the system for a case of bistability for the autonomous system with special emphasis on the effect of forcing on the periodic attractor of the autonomous system. When the centre of forcing is very close to the homoclinical termination point of the autonomous periodic attractor, period-doubling mechanism and Type 1 intermittency have been identified as the routes to chaos for this six-dimensional (6D) system. Chaotic behaviour occurs at very low forcing amplitudes which simulate small disturbances that are unavoidable in the operation of any industrial unit. While in certain ranges of the values of the forcing amplitudes the output amplitudes of the forced system are higher than their counterparts in the autonomous system, other regions show the opposite behaviour. Average gasoline yield in the bistability region for the attractor resulting from the forcing of the autonomous periodic attractor is much higher than that resulting from forcing the autonomous static attractor. This yield is very close to that obtained with the optimum steady state which is unstable and requires prohibitively high values of controller gains to be stabilized
Assessment of magnetic resonance imaging role in evaluation of failed back surgery syndrome
Background: Failed back surgery syndrome (FBSS) is a fairly common problem. Magnetic resonance imaging (MRI) with its multi-planar capabilities and superior soft tissue characterization is the modality of choice for imaging the postoperative spine.Objective: This study aimed to investigate the role of MRI in evaluation of FBSS.Methods: Forty-eight patients with FBSS were referred to Zagazig University Hospitals who had previous lumbar spine surgery. All patients were evaluated by history taking and radiological evaluation by dynamic x-ray and a post-operative spine MRI study that consisted of seven series: T1 -weighted sagittal & TI -weighted axial series, a sagittal & axial series for T2-weighted series, post-gadolinium T1-weighted axial and sagittal series and Heavy T2 MRI myelogram.Results: The major identifiable causes of FBSS in operated patients for lumbar disc herniation included recurrent disc herniation and epidural fibrosis (27 and 10.4% of our patients, respectively), and both occurred in 22.9 %, post-operative infected fluid collection in 10.4%, spondylodiscitis in 6.3%, spondylodiscitis with epidural fibrosis in 4.2%, filum terminal ependymoma and postoperative infected fluid collection with epidural fibrosis in 4.2%, postoperative infected fluid collection with spondylodiscitis in 4.2%, epidural fibrosis with spinal stenosis in 4.2%, pseudo- meningocele with RDH in 2%, both epidural scar & RDH with deposits in 2% and RDH with spinal stenosis in 2%.Conclusion: MRI is generally a safe and accurate technique, which has been proven to be the technique of choice in evaluation of FBSS with its excellent resolution and multi-planar capabilities
Curriculum Analysis using Harden’s 10 questions framework: Case study Faculty of Medicine and Health Sciences, University of El Imam EL Mahadi (2018)
Introduction:Curriculum analysis is defined as unpacking a curriculum into its component parts, evaluating how the parts fit together, checking underlying beliefs and assumptions and seeking justification for curriculum choices and assumptions.
Methods:This is a qualitative descriptive study analyzing the undergraduate curriculum of Faculty of Medicine and Health Sciences, University of El Imam El Mahdi by adopting Harden’s 10 Questions of curriculum development framework approach. Answering Harden’s questions reflects the fundamental curricular components and how the different aspects of a curriculum framework fit together.
Results:The analysis of the curriculum of Faculty of Medicine and Health Sciences, University of El Imam El Mahdi reveals a curriculum with interactive components. Clear structured objectives and goals reflect the faculty’s vision. The approach for needs assessment is based on a scientific ground, and the curriculum integrated contents have been set to meet national and international requirements. Adopting SPICES strategies helps the faculty and students achieve the objectives of the curriculum. Different motivated instructional methods are adopted compatible with the program objectives and outcomes. A wide range of assessment methods has been adopted correctly and reliably, and in alignment with the intended outcomes to assess the learning outcomes of the curriculum. The Faculty of Medicine and Health Sciences, University of El Imam El Mahdi has a favorable educational environment for operation of its curriculum and it has also a well-defined policy for curriculum management, monitoring and evaluation.
Conclusion:Harden’s 10 questions are satisfactorily addressed by the multi-discipline and well developed, well-structured, and integrated curriculum of the Faculty of Medicine and Health Sciences, University of El Imam El Mahdi. The curriculum supports the mission and objectives of the faculty
Effects of bubbler irrigation frequency on yield and quality of foster grapefruit under Khartoum State conditions
The experiment was carried out in private orchards at Tayba Alhasnab area of south Khartoum, Sudan, (latitude 15° 35´ N, longitude 32° 60´ E, altitude 380 masl) during 2013 and 2014 to study the effects of bubbler irrigation frequency on yield and quality of grapefruit under Khartoum State conditions. Five different frequencies of irrigation were applied at 3, 5, 7, 9 and 12 days. Treatments were replicated 4 times in a randomized complete block design (RCBD) and each plot encompassed 3 trees. The results revealed that higher yield and number of fruits per tree were obtained with 5 days irrigation frequency in both years. The 5 days irrigation frequency increased total yield of foster grapefruit by 39% and 8% in the first and second year, respectively, compared to the 12 day. The highest fruit weight was obtained with 5 days irrigation frequency in both years. Moreover, irrigation frequency every 5 days had the highest water productivity.
أجريت التجربة في بستان خاص في منطقة طيبة الحسناب جنوب الخرطوم، السودان خلال الفترة من 2013 وحتي 2014 لدراسة اثر تكرار الري الفقاعي علي انتاجية وجودة القريب فروت فوستر تحت ظروف ولاية الخرطوم. تم تطبيق خمسة معاملات مختلفة من فترات الري (3 و 5 و 7 و 9 و 12 يوم) وتكرارها في اربعة مرات علي نظام المربعات العشوائية الكاملة وشملت كل قطعة 3 أشجار. وأظهرت النتائج أن الانتاجية العالية وعدد الثمار لكل شجرة تم الحصول عليها مع تكرار الري كل 5 أيام في كلا العامين. تكرار الري كل 5 ايام ادي الي زيادة انتاجية القريب فروت بنسبة 39% و8% في السنة الاولي والثانية علي التوالي مقارنة بتكرار الري كل 12 يوم. اعلي وزن للثمرة حصل عليه مع تكرار الري كل 5 ايام في العامين. اضافة الي ذلك ادي تردد الري كل 5 ايام الي أعلى إنتاجية لوحدة المياه.
 
Homoclinicity in the dynamics of forced fluidized bed catalytic reactors
The dynamic behaviour of the non-isothermal oscillating fluidized bed catalytic reactor subjected to high and low frequency forcing is investigated. Resonance horns and period doubling loci inside the horns are constructed, using efficient algorithms, for different positions of the centre of forcing relative to the homoclinical orbit (infinite period orbit) of the autonomous (unforced) system. The analysis shows that the reactor behaviour is very sensitive to the position of the centre of forcing relative to the homoclinical orbit. For high frequency forcing (ω/ω0 = 5/1) with centre of forcing close to the homoclinical orbit, the system shows period doubling to chaos at very small amplitudes. For low frequency forcing (ω/ω0 = 2/1), incomplete period doubling not leading to chaos is observed in some cases and the new period adding bifurcation is also uncovered for other cases. The interactions between different resonance horns are investigated and the resulting bistabilities are elucidated. Quantitative methods proved that the strange attractors encountered are chaotic with one positive Lyapunov exponent and a Lyapunov fractal dimension between 1 and 2
Dietary fiber components, microstructure, and texture of date fruits (Phoenix dactylifera, L.)
Date fruits vary widely in the hardness of their edible parts and they are classifed accordingly into soft, semi-dry, and dry varieties. Fruit texture, a signifcant parameter in determining consumer acceptance, is related to the tissue structure and chemical composition of the fruit, mainly the ratio of sucrose to reducing sugars. This study aimed to understand the relationship between the chemical composition, microstructure, and texture profle of 10 major Emirati date fruits. The soluble sugars, glucose and fructose, represent ca 80 g/100 g of the fruits on the basis of dry weight (DW) while the dietary fber contents varied 5.2–7.4 g/100 dg D.W. with lignin being the main determinant of the variability. The textures of the samples were studied using instrumental texture profle analysis. While no correlation was found between the soluble sugar and texture parameters in this study, the diferent fber constituents correlated variably with the diferent parameters of date fruit texture. Lignin, arabinoxylan, galactomannan, and pectin were found to correlate signifcantly with fruit hardness and the related parameters, gumminess and chewiness. Both lignin and arabinoxylan correlated with resilience, and arabinoxylan exhibited a strong correlation with cohesiveness
Diagnostic performance and predictive value of rheumatoid factor, anti-cyclic-citrullinated peptide antibodies and HLA-DRB1 locus genes in rheumatoid arthritis
<p>Abstract</p> <p>Background</p> <p>We evaluated the significance of the genes, defined as <it>DRB1*04 </it>or <it>DRB1*01</it>, in rheumatoid arthritis (RA) patients. We focused on the role of genetic and serologic markers to predict disease activity and destructive process of joints.</p> <p>Methods</p> <p>Sixty patients with RA were examined. Radiographic changes were evaluated by (Larsen score) and disease activity was measured by disease activity score 28 (DAS28). The markers analyzed were: erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-cyclic citrullinated peptides (anti-CCP2) and HLA-<it>DRB1 </it>alleles typed by PCR.</p> <p>Results</p> <p>In this study, anti-CCP antibodies, CRP, RF and AKA were detected in 83.3%, 56.7%, 71.7% and 52% of patients respectively. HLA-<it>DRB1</it>*01 was found in 45% of patients and 35% of them had one or two HLA-<it>DRB1*04 </it>alleles. According to <it>DRB1*04 </it>subtypes, (<it>DRB1* 0405</it>) was present in of 80% them. For prediction of grade of activity, the independent predictors were anti-CCP (OR 19.6), and <it>DRB1*04 </it>positive allele (OR 5.1). The combination of <it>DRB1*04 </it>+ anti-CCP antibodies gave increase in the specificity and positive predictive value to 92% and 90 respectively. As regards to the prediction of radiological joint damage, the independent predictors were HLA-<it>DRB1*04</it>, HLA-<it>DRB1*01</it>, RF, and CRP > 18 (OR 5.5, 4.5, 2.5, 2.0 respectively).</p> <p>Conclusion</p> <p>Our findings suggest that anti-CCP2 is superior to RF for the detection of RA and provided predictive information on joint destruction and disease activity. The presence of RA associated antibodies (ACCP or RF) and/or the SE genes are indicative for a poorer radiological outcome and higher grade of activity.</p
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